If, say, a .50 engine makes comparable power to a .40 with a tuned-pipe, the .40 engine + the tuned exhaust/pipe will cost $60-150 more than the .50 and be 2-8 ounces heavier...
Maybe this is correct when it comes to .40size engines. However, if you look at the MVVS .91, it weights approx. 535 grams without silencer. With a MVVS tuned pipe and header, total weight is 755 grams. With a average muffler weight of 150 grams, there is only a 70 gram weight penalty with the tuned pipe. But for this extra 70 grams, I get an increase of 1000 RPM on APC12,5x12 ( from 9000 RPM open exhaust to 10000RPM with a tuned pipe!). And the lower noise is a great bonus! Conclusion is that if you want a quiet engine and a good power to weight ratio, the you have to get a tuned pipe! That's why F3A pilots use them
