Tried them both on my Xplorer. The green spring definately makes the engine rev more at initial take-off, giving more oomph right from the start. Once rolling, there isn't enough difference to really tell.

 

Cost - under $20
Installation - about an hour first time, 20 to 30 minutes if you did it once. Takes a screwdriver & about 3 or 4 sizes of combo wrenches. No problem at all.

 

no white spring didnt hurt top end at all. It just raises the enguagement speed a few hundred rpm. To put in perspective, when in reverse it hits the rev limiter just as it starts to move. Smetimesd it inconvienent but worth the performance.

 

kc335, how loud is the SuperTrapp? I'd like to do the same on my SP335, but don't want to make it too loud. The wife has to ride it occassionally.

 

buckeye, it depends on how many disc you put in. With 8 in better performance but louder than stock. With 12 in performance is still better but less noise than stock.