If you are racing at that speed and higher, you really don't use 6th. It would take a very long straight (more than most tracks have) to get up to redline in 5th. 6th is really for street use (principally cruising on the highway), and the high RPMs with the current 6th are annoying. The stock engine has plenty of power for street use with a taller 6th. One will just be more likely to downshift a little more often to speed up quicker on a highway.You guys really want this? The car doesn't have a lot of power and it seems like with a taller 6th gear by the time you reach 100 mph you'll have to have your foot on the floor just to maintain speed. I would do it if I had forced induction only.
It looks like a fairly easy change if the tranmission is already removed. I am thinking about doing the gear change when I have to replace my clutch.