Wow, Portugal. That's cool! There's usually up-to-date 1/64s on ebay, but I don't know what the international shipping situation is. I'd try that if you haven't already.
I wish I could do that, I don't know how to shop online and I'm scared to do it, I don't want to get in trouble with my dad and I know that there are NASCAR die-casts on ebay. In Portugal, we do live broadcasts of NASCAR, go to the NASCAR's website on the Schedule section (black menu at the top of the page) and pick the option "NASCAR INTERNATIONAL LIVE RACE BROADCASTERS", then go to "Europe" and take a look at a TV channel called "Sport TV", that's the one that Portugal does live broadcasts of all NASCAR competitions (Monster Energy Cup Series, Xfinity and Camping Truck). Have a nice weekend and keep up the good work.
Definitely recommend stripping the cars completely in paint stripper as opposed to whiting it out and using paper. Just make sure to be careful with it and wear proper equipment like goggles, gloves, and a respirator because stripper is dangerous.
You dont need parts in order to do it. All you need is an existing diecast (we refer to these as "donors") to strip and paint, as well as the tools to do so.
This isn't the exact one I use, but if you have photoshop you can take the red out of this one. Or use Powerpoint's "remove background" feature if you have the patience. www.google.com/search?q=nascar+gen+6+template&site=webhp&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjxzfnz_IbUAhUEsFQKHTFFADAQ_AUIBigB&biw=1280&bih=627#tbm=isch&q=nascar+ss+template&imgrc=s98kXVBB_NE6EM: