Yeh but realistically it won't cost that much. Like fully tunnable suspension isnt 20000, exhaust isn't 15000, chassis bracing isn't 20000, fully worked engine isn't 100000 and so on. Upgrades in the game (apart from the ecu) are freakishly over priced. A total build like that would be expensive yes, but nowhere nearly to the 500k mark. And the standard car is freaking awesome to begin with
