Yet another option: the Yoshimura R-77D. It is shorter and fatter than the R-77 with a dual outlet for that over-and-under shotgun look. Here are the prices for the slip-on (Motomummy, on sale, free shipping):
$360 all stainless
$405 carbon end cap, stainless body
$513 all carbon
Also available as a full system
Look past what these people are doing to what may very well be an engine that's not even broken-in yet, but wow that sound!
That is a Yoshimura R-77D full system on a 600 (no collector/cat), so it is a lot louder that a slip on. It does sound good though. I think it might be because the two exit tubes are different sizes (diameter and length), so two different notes are resonating at the same time. The R-77D muffler looks shorter, and the connector pipe looks longer than the R-77, so that it ends just as far back. A conical shaped shorty with the same dual exit pipes would be nice as a slip-on (retaining the collector/cat).
Motorcycle: 2008 GSX-R 750 - Money Paint - Green Halos - Full Yosh R77 - ASV C5 Series Shorties - LED Turn Signals - Zero Gravity DB DRK Smoke - Fairing Screens(homemade) - Bazzaz Z-FI & Z-AFM soon to come
This is brand new from YOSHIMURA! This is brand new... From YOSHIMURA! This is brand new