I run a port/polished cv that I did myself. Done a couple of motors. I actually love the little cv, and more so since it's been worked on. I did it just for the reason already stated, b/c I was running against all novarossi motors. Truth be told, I've got a brand new nova mt.12 in a box downstairs. I like the cv so much I just don't want to change it. And if I did, you know what?? Those same guys will still beat me. Because they are superior drivers. But the cv runs really well after the work. Hits jumps better, and accelerates better. So it does help me. I ran most the year just ported and not polished. After polishing everything is when I noticed the most difference. The cv is great for doing work on and practicing, it's cheap, and parts are cheap. But as for a os cv-r, or tr, or a nova, I wouldn't do anything to them because they are already built to be a race motor.