Thanks to Arissa for pulling the info

Not all available slots have upgrades, not all upgrades require specific slots. Enjoy the life of ever evolving code handled by a lot of programmers!

Intake (Front)
Intake (Mid)
Intake (Rear)
Engine
Exhaust
Cooling
Brakes
Suspension
Wheels
Tires
Body (Front)
Body (Drivers Side)
Body (Passengers Side)
Body (Rear)
Body (Hood)
Body (Roof)
Body (Spoiler)
Body (Windscreen)
Body (Windows)
Armor
Seats
Computer1
Computer2
Computer3
Phone
Radio
Mounts (Bod capped, Firm uses 1 bod space, Hard uses 2 bod space)