I don't care for pipes personally. I don't like the peakyness that comes with a 2-cycle engine on a pipe. It makes it hard for fine throttle adjustment when you're right around the RPM where the pipe boost kicks in.
Actually, I don't like a lot of the higher preformance 2-cycle engines for that very same reason...too peaky. It's a personal thing, but I like a 4-cycle better for 3D....and really all flying.

That said, the Webra GT .50 and the GMS .47 (my previous recommendation) are pretty good engines. I've owned them both along with the O.S. .46 FX. I don't like the entire FX series of engines, but that's another story.

Wiz