IIRC thrasher and transgo are the same style kit.
Thrasher is more money ( 90-110 )and you might get a new free t-shirt
Transgo is more widely used IMO and cheaper ( 50-70 )
TEP sells them on there site and I know a few guys on here that have TEP trans and they all have the transgo kits.
I am sure others will chime in too.