I took the Scanner up yesterday evening and this morning with the tuned pipe ... oh my ... there is a very noticeable increase in power! I put on an 11x6 prop and it does give me more speed than the standard engine with a 10x6. I love the extra power and I can climb and do verticals (not unlimited) with more ease. I wonder if I will change to a 10x6. Noticed the flight time hs dropped quite a bit though ... from something like 12 mins to 8 mins only. Still I love the power and as an icing on the cake, the plane is CLEANER!