Methodology

The dataset

352 verified auction sales of 2005–2012 Porsche 911 (997) cars, collected from the auction listings themselves. Sources: Bring a Trailer (212), Cars & Bids (140). Every sale is a completed auction with a stated hammer price. Asking prices and estimates are not in the dataset, and buyer fees are never added to a hammer.

The bands

Valuations use sales from 2021 on. A car is looked up by model, body, and transmission inside one of five mileage bands: under 15,000 miles, 15–30k, 30–50k, 50–75k, and 75k+. Heavily modified cars are left out of the bands; a documented engine replacement or cosmetic changes don't exclude a sale. Where a band holds 3 or more sales, the calculator shows the observed range and the median. With 1 or 2 sales it shows the actual prices. With none, it widens once to all transmissions for that model and body, says it did, and if that's still empty it tells you there isn't enough data. It never invents a number.

Adjustments

Documented work can be worth money: a clean bore scope and an IMS replacement on a 997.1 Carrera, pinned coolant pipes on a Mezger car, Sport Seats, PCCB. On 996Value.com the IMS adjustment is measured at +7.8% across hundreds of sales. The 997 dataset is younger, so every 997 adjustment is currently marked not yet measurable and changes nothing. When the data can support a number, the adjustment turns on with the number published here.

What this isn't

These are auction results: enthusiast-owned, well-presented cars, mostly. Private-party and dealer sales aren't tracked. A valuation here is a summary of past sales, not an appraisal, and condition can move a specific car well outside a band in either direction.