My God, like all of you have never played any GT game?
So, for the sake of info:
- since first GT game (1997) Car Wash process eliminates the handicap on aerodynamical performance gained by mileage of particular car. New Car have 100% of it's aerodynamical efficiency which goes down to approx. 10% with gaining "dirt" (car become matte). Car Wash restores original aerodynamic values.
- Oil Change is introduced in GT3 (2001), toghether with actual tracking of indivudual mileage for every car. New cars of GT3 would gain performance boost with changing the standard oil to high-performance oil, while with wear of the engine (game was tracking how much do you "torture" the engine) and mileage you oil would become "black" and your HP would gradually come down.
In GT4 Used Cars returned into series, and their oil was "black" in the start. Changing the oil would boost their HP values back to one stated when shown in Dealership-phase.
At some point - above 100.000 km travelled if I remember well - even Oil Change couldn't bring the HP value to the performance of the new unit. I am not sure does the Engine Overhaul process of GT5 allows that, so I will leave that one for the future debates.
I could also write down a book about Chasis Refresh and so on, but I'm not into mood.
All above is main part of Gran Turismo series "ownership/maintenance" philosophy in GT Career modes and it is connected only to GT-Career modes.
All Arcade modes - Arcade races, Time-Trial races, 2P races, LAN races (in GT3 and GT4) used "stock" cars with all above "ownership" features disabled.
