That depends on your requirements for modification. If you just want to turn around, I suggest you change the big surround and lighting. Central. Exhaust and install a big tail. This modification has no damage to the car. If you want to improve power and performance, first modify the suspension and hub. Next comes the intake and exhaust, the computer version, turbocharging, and finally the appearance. (This is the simplest modification) I don't believe you want to modify it into a car that can go on the track. I won't go into details about the more advanced modification. Modified cars need money to talk. Ask me if you don't understand anything.