I've ran them both quite a bit in gas truck. They're great engines. Equally easy to tune.

The CV is very underated for it's cost. It really does perform well. In gas truck the powerband of the engine is near perfect. It's very easy to drive consistantly with this engine. You can turn fast laps with it because it doesn't overpower the chassis nearly as easily as other engines. A lot of people will go slower with engines that have more power than this. If the surface is dusty and low bite, the CV is hard to beat. Being in control equals good lap times. The only negative to the CV is fuel economy. I have to pit at 5 minutes when running this engine. This can be a factor at big races with long mains.

The CVR is an awesome engine for gas truck as well. I can usually go 7-8 minutes on a tank with the CVR. It has a more powerfull midrange hit than the CV. This can be a good thing if there is good traction and tricky jumps with short runups. But, if the track is dusty and loose, the CVR will require more care to drive smoothly.

These two engines are an awesome value for gas truck because they are so much cheaper than the Italian engines, and they offer all the power you'll ever need.

If you are looking for a competitive engine for touring car they may be a bit underpowered. If you are relatively inexperienced with TC's the CVR is a good engine because you'll have less tuning issues to worry about, and you can concentrate on your line around the track. You'll definately be at a horsepower disadvantage if you're racing against experienced guys with Novarossi's, RB's, Mugen's, however.

Hope this helps