I know this is a bit old but i just joined the site seeking some information. I actually have a purple clutch spring for my 95 tcat 900. I have several different springs and for trail riding the yellow spring worked good enough. The purple one isn't really for trail riding in my opinion as your into the throttle too much therefore, you don't get crap all for gas mileage.It surely is nice to stick the purple one in the odd trip to have a little more fun.I also just purchased and set of 3 stinger silencers to replace the box and 3 k&n filters. Should sound a bit better and perform a bit better.