Yikes! How in the heck does an LT40 weigh in at 8.5 lbs anyway? The biggest performance improvement you can do for that plane would be for it to loose some weight!

I agree - when weighing the benefits ($$$) of a pipe -vs- a bigger engine, I'd always go for the bigger engine... unless you can drag one outta the bay for cheap. http://www.macspro.com/headers_side.asp lists a header for the Evo .40, and it crosses it with many popular brands of engines.... you may get lucky if you shop the bay.