Jeep Srt 8 Magnaflow X Pipe. If you're happy with the sound in the videos you've seen, then just get the Magnaflow X (assuming you need the X, not Y) or knock-off equivalent. Their gentler radius allows for better exhaust gas.
MAGNAFLOW 2006-2010 JEEP SRT8 GRAND CHEROKEE GC 6.1L HEMI ... (Stephen Aguilar)
Made in the USA and engineered to last, for those seeking increased performance and better economy, MagnaFlow MF Series Performance Exhaust systems deliver the smooth deep sound you want and the wide-open performance power you need. Kooks has been the leader in performance headers for some time. I want to get a better sound without losing performance.
I left to factory resonators in the back alone.
I wish Bwoody would have came out with these a long time ago, definitely worth every penny, the guys at Bwoody definitely hit this one.