We have done quite a bit of running on DLE 30's last weekend we were talking about a Pilot Rc 78" Extra that sounded great, people thought it had a full canister set up...but it doesn't it uses the OS 33GT Pitts Muffler. It's a bolt on fit and quieter and more rpm than a std DLE30 box.
Also prop wise we have done plenty of testing, moving away from the old favourite 18 x 8 prop. We are running between 18x12 and 20 x 8 in Graupner G-Sonic and 19x8 and 20 x 8 in the composite types.
Dw