I tried the TRG damper by using DIY modification (imitating X1) last year. Effect is good as done well in F1RCGP - stock classes. The DIY "triangle" plate came from broken 3R T-Bars, very easy to cut and make. And good if you do not have X1 or WGP like me... haha . . .. very cheap....
See Link http://bbs.rc-evo.com/forum.php?mod=viewthread&tid=221912
Actually I bought this part from RCMart, and took the two dampers out. Price is around $33x but you get two dampers. I used the additional parts, suspension mount, battery clamp, for other things, good deal.