You'll love the TKO600. I heard alot of complaints about it's shifting prowess,but I've no issues. It's a little notchy,yeah but it feels like a "real" manual trans.
I drove with a factory 3550 (TKO) for about a decade before I upgraded it. I've been using this transmission for 20 years now, and have gotten quite proficient at it. They can be shifted relatively quickly below 7000rpms. I did do the upgrades Hanlon recommended a few years ago. 2-3 is always a little dicey, and you need to take just a little more time with that shift. If it ever dries up here, I'll try and get someone to hold a Camera and make a video. You guys are going to yourselves when you see how fast a Hanlon prepped fully synchronized TKO can be power on shifted by an old fart that peaked a long time ago.