Like previous comments mention, totally different racquets.
I played a couple of hours with the Extreme and didnt like it at all. Very stiff and powerful. I had a hard time keeping the ball in the court. I love to serve with it though, the ball just exploded on first serves. To me, the Extreme had a "babolat feel" if that even makes sense, hehe.
LM radical on the other hand is a more control oriented frame than the Extreme, softer and with a denser string patterns. Even though it has some punch, its not too hard to control.
If you havent played with either, I would say demo first. For me, the LM Radical is hands down a better frame than the extreme.