Exhaust Questions

Alright, well as of right now i have a big gun race series, bought it off some member for 100 bucks. it get's the job done though, i gained power from it. had it bout 6-8 monthes. but now, its just starting to get annoying, it makes my quad sound like a stock one, with no baffle, just louder. And i put packing in the muffler 2 monthes ago( which made it quieter, but now its back to normal) my question is, is it just the pipe that makes it this loud, and sound like crap? or is it just the way YFZ's sound?

my quad is super high pitched compaired to my friends piped LTR, or my other friends 450r, there's has a low, kinda rumble, mines a high pitched annoying! ha. even at the track,there was a YFZ with a duncan exhaust, and it was deep like the other 450's

also, i heard a very good quiet-er pipe is the Dr.D. does any one have one?? how did it do on power? how loud is it?

thanks yall!

-Nathan