im a dl 50 owner and my experience has been as expected for the 285 i paid from canada ,it pulls my 30% yak from hover at 3400 feet altitide,,with a well balanced vess 23 a w /super unleaded  no ethanol gas,stock muffler,but honestly ,instead of buying a tuned pipe ,i replaced it with a mt57cc,,now it really pulls out,,,but back to the dl...it starts good it runs strong cost ,,what 350.00 lesst than a da ,its worth it even with the leaky plug threads  and lower grade aluminum and the endplay (check yours) theyre great  meybe a better quality case on ign ,tighter bearings,end play and theres no reason they shouldnt give a better moffler a few thousands os an inch is all it takes,the fix is cut it short,and put a bead of jb weld around the seam ether before it breaks or after or just buy an aftemarket,ive put the dl 50 on a smaller 82  inch plane ,perfect ,im sure they will be cheaper now since the 55 and the one the resembles it from hobby city for 235.00 im sure any good tuned pipe will incerase performance ,,but its only my opinion its better to find one made for what you really want mt 57 400.00 da you know but theres several others but bottom line worth it,theyre good.