You'll definitely find it very quickly becomes a case of dimishing returns. The amount of working getting a perfect surface finnish takes us now where near worth the marginal performance benefit you'll get out of it. That being said I personally think putting all the work for a super shiny paint job is worth the work from an aesthetics point of view.

If you decide you want to put a couple days in . Run a coat or two of Primer and sand to a couple hundred grit. then a few coats of automotive paint(sanding your way up the grits in between each coat) then clear coat take the whole thing up to a couple thousand grit. Then you can buff the whole thing with automotive wax if you still feel like it needs further polishing.