[Logic]

How about a Auto Store. Something simple

Once you perchase a car(Or already have one), you can tune it up a bit.

Once you get enough mileage, you usually need oil. That shop can sell it.

Or if you're going for a sporty type whip, you can put 'NOS' on the car(To make it go faster)

Other items,1-Bigger wheels(Drive off-road easier)2-Slicker Wheels(To drift easier)3-etc.

Just like a store.

Mine for the minerals to make the NOS and other items.

That could add more items into the weapon parts store