Repaint questions

I posted before that I wanted to use this Scalextric RTR Camaro

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.
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.