I like the Thunder Tiger Pro 46, I have 2 of them, I would choose the Pro46 over the FX and LA, I cant speak for the others... but LA is underpowered and it has a nylon backplate that I heard could possibly break, I like the FX's but I dont like how the remote needle valve is set up on it, sometimes its hard to get to the fuel line, and it would be worse because the Thunder Tiger trainer has a cowl exactly like my tiger sport does, making it harder to fuel up with the way the RNV is set up on the FX (you could always use a 3rd fuel line)... I have also had a problem with air leaks on the FX, simple change of the fuel line from the RNV to the carb fixed that though.

Good Luck.