I finally got my Terminal Velocity installed and as far as I can tell so far, it's been a good choice for me. I also did a cam change to the S&S570 at the same time with a cometic .030 head gasket, but the bike runs great now. I'm not sure how much to attribute to the cam and how much to the TV unit, but it runs great and I didn't have to tune anything. I have an 03 SERK with factory 103, SE air cleaner (not the stock one-it's not really an SE unti) and Rinehart true duals. I was using a Techlusion DFO but removed it to install the TV unit. I have no dealer downloads to the ECM, but the TV unit seems to have been able to correct all of that. I only have about 35-40 miles on it so far (too cold) but it has improved a lot just in that amount of riding time.
When I first started it, it idled fairly poorly, but kept improving as it ran. Rode about 1 mile the first night and it wasn't too bad. Put another 12 or so on it and it got quite a bit better and today I managed about 17 miles more ( remember it's in the 30's here) and it seems to be running great. So as soon as it's warm enough to put some miles on it I really thing the Terminal Velocity will be a great addition. And no dyno tuning expense, and most likely very good tuning.
So far I'm happy and the install was pretty easy as I had the exhaust off anyway for the head gasket change, so it was easy to weld the bung in. As far as my experience so far, I'd buy another one rather than something else. Like I said, no downloads in the bike at all!!!