hangslo
+1y
I'll try not to write a short novel on this, but bear with me bro ...
There are acrylic and urethane single stages as well as acrylic and urethane basecoats. Your choice is going to depend on several factors and their order of importance. Cost, ease of application, expected finish, color, longevity, etc. If you are shooting a solid color then single stage could be used. Generally, an acrylic urethane will hold out (depending on color) anywhere from one year to 5 or more ... depends on the color, level of care and maintenance, and if it is garage kept or not. A polyurethane (catalyzed) should last at least 5 years or longer also depending on the above conditions.
If you are shooting a metallic/pearl, then base clear is the way to go, but that doesnt mean it has to be expensive. I am assuming that you are going to want to go base clear, and if you do then there will be no option for you to use anything other than a polyurethane clearcoat. If someone tells you they have an acrylic clear, lacquer clear, or the latest and greatest thing but it isnt urethane, then RUN AWAY.
You can get a cost effective base clear job with the right products as well as prep. If you are going to spray a solid then by all means, you can use a single stage urethane ... as long as the truck is prepped right and the product is applied right it will look like base clear. I painted my 95 XCSB with single stage and when I sold it 4 years later everyone still swore I sprayed base/clear on it and it was just as shiny as when I painted it. And it sat outside everyday, and I drove it like I stole it.
I work for a manufacturer, but would be more than willing to help point you in the right direction with other products as well ... not trying to steer you in any one direction. Hope this helps.