with the arcrylics, you have acrylic enamel, then you have acrylic urethane. both are single stage and need no clear. also both went out with the dinosaurs.
the product you should be looking for is a urethane two stage system. thats whats best for a metallic finish. if its a solid color, you can get a real good job from a single stage with no clear, arguably a better shine than clearcoat can provide. but the shine in the job comes from the colorsand/buff, the products, or the application. not from the gun.
for what its worth, if a car is prepped correctly, the crappiest paint will last a lifetime. this flimsy 5 year warrantee has little to do with the longevity of the paint, its more of a risk assesment of weather or not you will go back and complain in a few years. thats right, complain to maaco about a bad paint job. go ahead, theyll just hack it up again.
remember, good painters do work at maaco, cars just get no attention before, or after the paintjob. the two times it counts the most.
94 V8 on 17" custom paint, R.I.P
97 Mark VIII LSC yeah
08 Ford Edge, white for now