Here is a quick list of pipes, and yes I threw my hat in also, if anyone else would like to add please do so.

Aaen      Q-V1 Copy, Midrange and Top End
 Heard that Aaen did do some upgrade changes to fix fit issues and performance, offers different silencer packages.
New Raw $400, Ceramic Coated Additional Cost , Spark Arrest Silencer Additional Cost 

Q-V1      Great mid and Top End Ripper Had pulls to 8500 RPM / Reports of brackets and pipe cracking - No spark arrester
Used $400 to $600 Pipe is nickeled plated and polished

Q-V1.1   Good Bottom End Strong Midrange pulls to 7800 RPM have Data on this - No spark arrester
Were only custom made / Used $500 to $700 if you can find them, only a few were made. single plated chromed

Q-V2      Still waiting on Dynos to see the power band - No spark arrester
Heard $820 Shipped and have to pass the RK screening - Nickeled plated and polished

HPR#19 Great Bottom, Very Strong Midrange and pulls to 7500 to 8000 RPM - No spark arrester
New just under $1000 - RAW, Used we seen $820 only one seen so far for sale - From Play Dunning to ALL OUT RACING!

DCS-6   Great Bottom, Good Midrange, Pulls to 7500 RPM to 8000 RPM - With Removable Spark Arrester
New Raw $650 Have dyno charts, pipe is set up more for Trails and all around Play Dunning