I'd tell you not to change any of it. It's not your car. I'd much rather spend money on a car I owned rather than one I didn't, and even if I owned the car I'd think twice, preferring to keep the money and keep the car as is at least initially (example: the car came with wheels and tyres; I'd use those...). Since the duration of a least rarely extends beyond what is implied in "initially" above (2 years?) I'd stay with a stock car.