Pie, the dual cell mod forces you into a bunch of other mods to get control of what you created so it's wise not to get into it unless you dig working on tiny weenie things.
100% black colored silicone is available in squeeze tubes from either a local hardware store or automotive parts store. Think I used 'DAP' brand. but easy to make once you get used to spreading the stuff onto the tires with a slick strip of mylar.
The only reason I got into it was for the custom width of my tire set up, you probably dont have to do a darn thing to a stock car, although the silicone coating makes for some pretty sticky grippy tires. You'll make a mess the first try but just let it dry overnight (needs to cure for 12-24 hrs) then peal it all off and try again till you get it just right.
Thanks for the pics Strider! You probably have better accelleration due to a lighter wheelset but do you have enough sticky rubber on the road to do a wheelie?

Is that a dual cell car? No flipping with that set up?