How big of a difference does it actually make? How fast does it shift? Does it make you go any quicker 0-60? Does it rev to the redline or still shift @ 6,100? Does it kick down a lot more when you go to pass someone?

i dont know about the 60', but i notice the car shifts a little quicker. that depends on how much you open up the holes in the valve body.

the rpm range is the same, the actual switching of gears is a little quicker though.

dont even worry about the performance aspect of the kit, just do it as preventative maintenance for the trans...

I say get it too. I've got the directions on my site if you wanna give it a look and see if it's something you wouldn't mind doing. It looks alot harder than it is.