SPI all the way for me and I am no apology an amateur and I can get a good job with it so the experts should have no issues. Black epoxy for chassis and under hood, grey for body and universal clear. If you need a good sanding/filler primer use the SPI turbo as it is ready to sand in 20/30 minutes. Universal clear will lay out wet and slick so mimimal buffing is needed..
I have tried most all of it and now do what is known to work..