ORIGINAL: FalconWings
Bypass and tailpipe size would affect it greatly. I have a P-120 size bypass/TP, so no matter the engine size I will have lot's of cool air flow. I could see a potential performance loss if a P-70/RAM500 size bypass was used, as a P-80 would block 90% of the bypass air. You'd probably cook your tailpipe eventually too.
I flew my BARF on a P-70 a couple of times and didn't really like it. Not much mojo.
Ya Im kinda of looking for that "oomph" out of it. Something with a wide range and that low end punch when you need it..Im thinking that p-100 might be it. Smaller, lighter, than the p-80se with just about the same thrust..