The Aaen pipe is almost the same as the Q pipe performance wise...From what I was told is was made because some had issues with the Q pipe hanger breaking on the pipe...I had a Q pipe on the Zilla I had and have an Aaen on a hybrid and both work very well.I never had an issue with the hanger on mine and got it used from a member here.Sometimes they show up on ebay...The Q pipe does have more "bling" for looks though.There was also a Dr Q 2.0 that was supposed to come on a little lower in RPM but without as much overrev on top....

Before the Q pipe I ran the PT pipe.It worked ok but Had nowhere near the top end power of the big volume pipes...What kind of riding do you do???

I have no experience with any DynoPort pipes but apparenty the 250 one is a good one...Maybe PM Iceracer on here as he has done alot of testing on the 250 Dynoport,I'm sure he'll have some input on the 500.

Also the "best pipe" available from what others have said is the HPR pipe.....Contact MotorGeek on here,he makes the pipes and also does Porting,engine work...Supposed to be one of the best...

Hopefully some others will chime in and give you their input/experiences.