Porsche 911 GT3 (997)
Why 5.5: Mezger flat-six, hydraulic steering, a six-speed manual and no PDK option at all — and unlike the 996 GT3 above it in this list, Porsche federalised this one, so the American population arrived through dealers rather than through the import rules. The 997.2 added 3.8 litres, centre-lock wheels and 435 hp.
Layout
Natural habitat
Ride comfort
Sound
The Mezger flat-six is the racing engine of the line, hard and metallic to 8,400 rpm with nothing in the exhaust path to soften it. A fraction below the 992 GT3 only because the later 4.0 finds another 600 rpm to stretch through.
6-cylinder · naturally aspirated · 8,500 rpm redline · rated 8.9 / 10 for engine sound
Market value
Median asking price, good condition · €104k (2010) → €161k (2026), trending up · illustrative data
Child seats · ISOFIX
There aren't any — strict two-seater.
The only position there is, so makers of this era equip it: expect a passenger-airbag cut-off (key switch or occupant sensing) as standard, because there is no rear row to point children to. Whether the seat itself carries ISOFIX anchors is maker-specific — Porsche bundles them with its child-seat preparation, Ferrari sold them as an option, others are belt-mount only with the airbag off.
Derived from production years and seating layout, not a per-car source. ISOFIX was standardised as ISO 13216 in 1997, required on new EU model types from 2011 and on all new EU cars from 2014.
The long version
For a long stretch this was the cheapest way into a Mezger-engined GT car, which meant it was bought by people who wanted to use it and could afford to consume tyres doing so. That has shaped the fleet more than anything else: 997 GT3s show up at track days in numbers that almost no other six-figure Porsche matches, and the specialist support network exists precisely because these cars accumulate hours rather than sit. Values bottomed around the middle of the last decade and have climbed steadily since, as the combination of hydraulic steering, a naturally aspirated engine and three pedals became a category rather than a spec sheet. The climb has pulled some cars off the track and into collections, but the paddock population is still the defining fact about this generation.