What about an Upgrade shop. Like at the Pay and Spray. Where one could add turbo kits, or lift kits for trucks etc.. You know, like Forza or GranTorismo.
Forget these zero clearance cars that should bottom out at the slightest hill, break out a Ripsaw EV2.
2 seats, 750hp, 100kph top speed, 100 cargo, tracked luxury vehicle.