The UCD .46 is a great 3D trainer. Not the best 3D aircraft out there by any means, but it's great to learn on. Gotta get the CG waayyyyy back to be able to do some of the stuff really well.

IMO, you want to put a Saito .91 in it... There are a few guys with Saito 1.00s in them.

If you do a search, there are pretty large threads here somewhere for both the UCD and the Mayhem, these should help you a lot.