I busted my T5Z and decided to go with a TKO 600. I crunched the numbers and determined that the G-Force wasn't really any cheaper once you add everything up. Plus I got a brand new tranny instead of one that was basically rebuilt. The Tremec is a little heavier, but you can't get something stronger without adding some weight. Plus the Tremec case is stronger. You can put whatever internals you want in a T5, but the case still isn't all that strong. My Tremec shifts great BTW, not rough or tight at all.