I have the RB CE 3 port in my Storm. It's RB's economy engine and even though it's only a 3 port and entry level, it screams. Not C5 or S7 fast, but it'll get the job done. Great low end punch.
itsmesag1 is right. If you have ever seen those high end RB's run, they're blazingly fast. Uncontrollable in the hands of mortal men. Then there is the price of these high ends mills. I paid $149 for my CE and you probably could get one for less if you shopped around. Either way, if you go with RB know that you've chosen a quality built, race proven engine.