Pipe on Sig Chipmunk?

I read Dee Rice's article on his Oriental Plus. I'm wondering if I could put a similar setup on a Chipmunk I'm building. I'm worried that I might mess-up the CG too bad. Any thoughts?

You would have to make room underneath. That is the only real problem. (That, and make some leg extensions for the gear before you close up the wing).

CG shift should not be a problem unless you choose a heavy engine up front. The pipe will flow to the back--some ahead and some behind the cg--and overall weight increase, for the pipe alone, won't be that great.

What engine were you thinking of?

Is was thinking of using the same ROJett engine set-up Dee used on his. I had orignally purchased an OS40LA for this plane but after reading Dee's article, I can't stop thinking about the pipe.