Home/Services & Pricing/Technical Due Diligence
On-site appointment · model-specific inspection planAn in-depth physical assessment where the car is: we travel to the car and assess it against a model-specific inspection plan. Facts instead of gut feeling, from €790 incl. VAT plus travel.
Technical Due Diligence is the 911Finder on-site appointment: the in-depth physical assessment where the car is, before you buy. As an independent technical representative of your interests, we look specifically for weak points, with paint thickness measurement, a diagnostic readout of the control units, a technical check and a test drive.
The distinction is simple. The Digital Audit assesses the listing and the paperwork on hand, once. The Purchase Advisory carries the remote work further. Technical Due Diligence assesses the actual car.
Assesses the advertisement and the paperwork: a remote review of the listing, the history and the market data. Fixed price €199 incl. VAT, delivered as a PDF dossier within 24 h.
€199 incl. VATCarries the remote work further: Digital Audit included, up to two bundled rounds of follow-up questions, assessment of dealer answers and of documents supplied later, a negotiating strategy. One car, up to 21 calendar days.
€499 incl. VATAssesses the actual car: an assessment where the car stands, against a model-specific inspection plan. From €790 incl. VAT plus travel at €0.59/km.
from €790 incl. VAT + travelMany clients use the Digital Audit as a first filter and instruct the on-site assessment only once a car has passed it. That saves you pointless viewing trips.
The assessment follows the scope of the official Porsche 111-point check (vehicle documentation, interior, wheels and tyres, drivetrain and underbody, bodywork, engine bay, fluids, test drive) and adds the model-specific points of the particular model series .
The VIN is cross-checked on the body, the type plate and the papers. The service book, original invoices and registration history are examined and checked for plausibility.
The first start is made with the engine cold: starting behaviour, idle, smoke and unusual noises show themselves most honestly here.
Reading out the control units: the fault memory, the over-rev readout for rev ranges 1 to 6 with operating hours, and the plausibility of the odometer reading.
Underbody, oil and coolant leaks, suspension, brake system and tyres including their DOT date codes.
Paint thickness measurement on every panel, panel gaps and bolt heads as signs of removal. The aim: to test the plausibility of the claim that the car is accident-free.
The engine under load (on turbo models, how the boost builds), the clutch with its bite point and any judder, how it shifts, the damper maps, braking performance and straight-line stability.
Should anything come up during the viewing, it is documented openly and settled before the purchase is concluded. Optional, at your request: an additional check at a Porsche Centre, for example a leak-down test. An independent check by a Porsche Centre or by an expert of the buyer's choosing is expressly supported.
Every appointment gets its own inspection plan, tailored to the model series, the model and the paperwork of that particular car. What that looks like is shown by this anonymised extract from a real inspection plan for a 997 GT2.
The 997 GT2 uses the robust Mezger engine (GT1 block), which by design does not have the known weaknesses of the Carrera units (IMS bearing, bore scoring). A few points nevertheless deserve particular attention:
| Inspection point | What is checked at the viewing | Background |
|---|---|---|
| Coolant pipes (GT1 block) | Visual check for traces of coolant at the pipe joints, a question about pipes that have been pinned or welded, a pressure test of the cooling system | Pipe sections bonded at the factory can come loose after many heat cycles, the best-known weak point of the Mezger turbo models |
| VTG turbochargers & linkage | How the boost builds on the test drive, throttle response, readout of the actual boost values, checking the linkage for play | The adjusting linkage of the variable turbine geometry can develop play |
| PCCB brake system | Visual check of the discs for chipped edges and cracks, pad thickness, a measurement log where appropriate | Ceramic discs are long-lived, but replacement is expensive, so checking their condition belongs to every GT2 viewing |
| PASM dampers | Visual check for oil seepage, function test in both damper maps | Dampers can develop leaks with age |
| Over-rev readout | Readout of rev ranges 1 to 6 with operating hours | Documents whether the engine has ever been over-revved, important on any GT model |
| Tyre age (DOT) | Check the DOT codes on all four tyres, rule out flat spots | On a low-mileage car the tyres are often older than the tread depth suggests |
An anonymised extract. The full inspection plan covers further points, such as the clutch, the radiators and condensers at the front, and the typical issues of cars that have stood for long periods.
Porsche describes the 111-point check publicly in more detail than many buyers assume: bodywork, paint and possible accident damage, vehicle documentation, the fault memory, odometer plausibility, over-revs, drivetrain and underbody, how the engine runs and a test drive are all expressly included. Anyone claiming that Porsche only looks at the surface is wrong. The difference from our assessment lies not in the number of ticks, but in the question being answered.
| Aspect | Porsche 111-point check | 911Finder Technical Due Diligence |
|---|---|---|
| The instruction | A standardised quality check by the Porsche Centre. On a car with no existing warranty it is a precondition for the Porsche Approved Warranty. | A buying decision on exactly this car for exactly this buyer. |
| Perspective | Carried out by the Porsche Centre to the manufacturer's programme. | An independent mandate on the buyer's side, with no commission from the seller. |
| Inspection logic | A fixed programme of 111 points. | The basic scope follows the 111-point programme, extended by hypotheses drawn from the listing, the paperwork, the known risks of the model and your own questions. |
| The result | A quality status and, if the car passes, access to the Approved Warranty. Which report you are given as the buyer is a matter to settle for each instruction. | A condition report with the control unit logs, the open questions, a buying recommendation, conditions of purchase and a negotiation brief. |
| Relation to the market | Not part of the publicly described programme. | Findings, history and specification placed in the context of market price, liquidity and resale. |
| Strength | Official manufacturer documentation and access to the Approved Warranty. | Independence on the buyer's side, model-specific depth, and the car, the paperwork and the market data brought together. |
| Limit | A standardised check cannot guarantee that every latent or intermittent fault will show itself at the moment of inspection. | Without dismantling or additional diagnostics we cannot guarantee a hidden condition either. Points that cannot be checked are marked as unverified in the report. |
Source for the scope of the 111-point check and the warranty options: porsche.com, the German pages „111 Punkte Check“ and „Porsche Approved Garantie“, retrieved on 1 September 2026.
The two do not exclude each other. Where manufacturer documentation, eligibility for Approved status or a deeper workshop diagnosis is needed, we expressly bring the Porsche Centre in. That is why every Digital Audit names the right route for that particular car: the Porsche Centre is enough, 911Finder is recommended, or both together, for instance with high-value GT cars, an unresolved question about track use, an unusual price or a complex history.
Track use as an exampleEarlier track use can usually not be ruled out with absolute certainty. We work through the typical indications systematically, set them against the data and the history, and state the remaining uncertainty openly.
| Area checked | Possible indications | Limit of what it tells you |
|---|---|---|
| Wheel arches and underbody | Rubber deposits, stone-chip patterns, contact marks, damage | A single feature does not prove track use. |
| Tyres and wheels | DOT age, wear pattern, signs of heat or abrasion, fitting marks | The tyres may have been replaced before the sale. |
| Brake system | The condition of the discs, the pads, signs of heat, PCCB edges, documented replacement | Spirited road use can leave similar traces. |
| Vehicle data | Operating hours, odometer plausibility, over-revs, fault memory | Unremarkable data is no proof that a car has never been on track. |
| History and statements | Invoices, statements from previous owners, photographs, events, modifications | An explanation is only strong once the sources behind it hold. |
incl. VAT · + travel at €0.59/km from our base on Fehmarn
The assessment is carried out by Thomas Ottenstroer, founder of 911Finder: technician and former workshop manager , with hands-on technical experience and a clear specialisation in the various generations of the Porsche 911.
The fee starts at €790 incl. VAT. Travel is charged in addition at €0.59/km from our base on Fehmarn. All prices for private clients include statutory VAT; trade prices on request.
The Digital Audit & Market Check (fixed price €199) assesses the listing, the paperwork on hand and the market data, once. The Porsche 911 Purchase Advisory carries the remote work on through follow-up questions, dealer answers and documents supplied later. Technical Due Diligence assesses the actual car, on site.
A detailed condition report with the control unit logs, a buying recommendation and a negotiation brief covering every fault found, which you can take into the price negotiation.
No. A viewing does not replace the German statutory roadworthiness test (Hauptuntersuchung) under §29 StVZO. An additional independent check by a Porsche Centre or by an expert of your choosing is expressly supported.
The 111-point check is a standardised quality check by the Porsche Centre to the manufacturer's programme; among other things it is a precondition for the Porsche Approved Warranty on cars with no existing warranty. Our Technical Due Diligence is an independent mandate on the buyer's side: it follows the scope of the 111-point programme, adds model-specific inspection points and hypotheses drawn from the listing and the paperwork, and answers the question of whether you should buy this particular car at this price. The two can complement each other well, and the comparison sets out the differences in detail.
Directly where the car is, at the dealer or at the private seller. Travel is charged from our base on Fehmarn at €0.59/km.