[excelpoint]

I would say the opposite to 3D Seth. The 45 on a tuned pipe would be ok for 3D but would not be suitable for IMAC. IMAC is where you need the power not so much 3D. Realistically most of the moves in 3D are post stall so you are at fairly low rpm, you do need a bit of power to pull you out of a hover. In IMAC power is more important for good uplines etc especially when you have snaps etc on uplines, thats when you need excess power to pull you out the other end and still climb with authority. Ive had two 2.3's one with a DA50 and tuned pipe and one with a ZDZ80. The ZDZ80 was a much better choice for IMAC but the DA50/pipe combo was better in 3D because of the lighter wing loading due to the lighter engine. Ive also flown a 2.3 with DA50 and standard pitts muffler which was ok for general flying but struggled in the Sportsman IMAC sequence. A mate of mine is currently building an Extreme Compiste 2x2 Edge for his Evelution 45 really nice looking bit of kit, or ID look at the Comp ARF 2x2 both would be more suited to your 45. JMO
Cheers Matt