I did!
I had a 2001 SS 6spd. I really only miss the t56 but other than that I love my Mach and (I hate to dsay this) but i do not miss my SS with it's oil consumption(bad ring, I had to change #1 cylinder sparg plug every two weeks), piston slap, clutch problem, power window problem and ofcourse couldn't run et srteets because of the glass rear end. The LS1 motor DOES run hard (my other friends LS1).