The only aerobatic airplane I have seen that was louder than a racer was a DA-100 with stock pipes turning a Menz 27-10 at full throttle in level flight. That was ear-splitting, but also an irresponsible way to fly a plane like that. Racers, on the other hand, live to fly at full power the whole time. Fortunately the aerobatic planes have throttle servos so everyone doesn't have to cover their ears in the pits. Here's a hint to you guys running Nelson engines with no throttle servos - if you feel the need to be wearing hearing protection when flying your plane then everyone else at the field should be too. Please bring extra earplugs.

Sorry about going on a rant about racers, every time I see a picture of one I think about the club I belonged to and cringe.