I agree with someone's other post: call David at Wyvern Creations, he will definitely give you all the information you need.
Having said that, I just wen through what you're going through... trying to figure out what crossbow would suit me best. After doing some research and handling a lot of them, I decided on the Parker Tornado, which I am extremely happy with.
Personally, I don't think you can find another crossbow in this price range that's any better. It's balanced well, fast, and extremely accurate. I split one of the vanes after only shooting it a couple times at 20 yards, because the groups were incredibly tight. Parker gets a bad rap for limbs, but this does not apply to the Tornado, and Wyvern will tell you this. The limb problems Parker had was on the (I think) Buckbuster model, and I believe it was corrected, but in any case does not apply to the Tornado.
The only drawback--as with any crossbow--is it's louder than the average compound, but it is fast! Unlike many crossbow manufacturers, Parker does not over estimate the speed of their crossbows, the Tornado will absolutely shoot 330 fps, and it is very compact.
I couldn't be more happy with my decision.