SHO Sho did a dyno test with their Y Pipe on the MSDS and supposedly there was a significant difference.
The general consensus around here is (If I recall correctly)
1 MSDS WITH optomized Y best gains
2 MSDS With MSDS Y pipe SECOND BEST
3 MSDS with BAT/Sho Shop Y 3rd best
But True Duals would give you the best gains overall
