On Mem card 2 which is at 100% + All Golds, I have
a Tahiti Blue Mini Cooper with ~174HP and 1456.5 miles on
and F090/S with 958.8 miles.
On my current game back on mem card 1, (~60.3% + All Golds, but beginner & amateur leagues practically untouched) (I wiped the 100% game off there by accident and just HAD to start again! Shame!) I have,
a Tahiti Blue Mini Cooper with 69HP which has 736.3 miles on from doing every road race in easy, normal & hard in arcade mode.
Then there's F090/S with 972.0 miles on from Formula GT,
F687/S with 962.8 miles on from Formula GT,
F686/M with 944.0 miles on from Formula GT
and F688/S with 941.1 miles on from Formula GT.
I have F094/S and F094/H waiting in the wings ready for their shot at Formula GT too.
Why the discrepancy in miles for Formula GT? I let each car complete each race, and run on autodrive after the race, for as long as it takes to display the times for each car, points, and total points. For the F090/S, F094/S and F094/H the autodrive seems to drive sensibly, changing gears well and this puts almost another complete lap after each race on the car, adding to the miles.
For the V6 Turbo F1s, for some reason the autodrive squirts the car up to the redline, in a particular gear, changes up and then drops the revs back down to 7000-ish, then changes down, squirts up to redline, etc etc, and does it over & over again, this means that if the car gets down to 1st gear it usually does most of the post-race auto drive at ~40-50mph, and hence gets less autodrive miles on.