I'll throw in my 2 cents. I am very pleased with the ease and final finish of PPG ShopLine Acrylic Urethane Direct Gloss. It's a single stage but you can use clear over it if you desire. The Direct gloss is amazing without a clear. I used it with an air brush and a conventional siphon feed Binks model 7. I did not do a full vehicle paint job, two different projects, my Vette needed some stone chip and minor panel painting, a jet ski had some fiberglass damage and paint work.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy