I have one of the TAV 2 clones on my predator. I love it. This is on a Brooks trail bike. Just Saturday, I took it out for a long fall ride, took some hills steep enough that I had to lean forward to keep the front wheel down, that Predator/TAV combo pulls like a team of horses.
I did not have to alter my aftermarket TAV, but I did also have to remove the little tin plate on the bottom of the head on my Predator. Also, because my Brooks bike was not designed to have a TAV connected to the motor, I had to elevate my engine mounts a bit, so my TAV could angle down without hitting the bottom frame-rail.
Totally worth the effort.
I bought one of the Chinese torque converters on ebay, I think I paid $179 shipped, but they have totally dropped in price and seem to be selling for about $120-135 shipped. I was a bit worried, but have had it for a yr or two and put many hrs on it and it has performed perfectly.