to create this actual SCCA Trans Am livery

I've only repainted one other RTR car and I just put a new coat of paint over the existing livery. That's what I'm inclined to do with this repaint but thought I'd ask what others would do. Is there a reason to strip the current livery off down to bare plastic and start there? What about a primer coat - needed or not if I just cover what's already there?
I also have a plain white Scalextric 1970 Camaro I want to use to create this livery.

Both of the new liveries are as simple as could be, one color body with a few simple numbers added. I have or will find stick on numbers at a craft store for decals.
My default paint for slot car stuff has been Krylon spray paint from Walmart. I already have a large assortment of mostly full large spray cans on hand, but it seems Tamiya is the preferred paint by folks into modeling. I looked up the Tamiya paints I'd use if I had a source for them - TS-8 Italian red 85008 and TS-17 Gloss Aluminum 85017. Since the nearest hobby shop is 90 miles away, what is an online source for Tamiya paints?
Any and all input appreciated.