I duplicolored my interior a couple months back, using the harbor freight gun. Despite others experiences, no peeling or chipping to date, but its only been a couple months. The prep work is key, and I spent alot of time trying to get it right before spraying. There's some pics of mine on an older thread. The Harbor Freight gun worked just fine for me. You get much more of a matte finish and much better texture than if you roll it, in my opinion. With the air compressor, the PSI you spray at will also affect how grainy the final texture looks.