Frame looks real good! Did you say that you're going the POR-15 route? I had the subframe for my Firebird powdercoated and after the fact I started to think about the inside of the frame. Eastwood sells this stuff made just for inside a frame. They have it in cans with a long hose/360 nozzle attached. It might be worth looking into before you finish the external portion of the frame. I want to do it on mine, but I'll have to strategically tape off the holes.