Ive got mine and I love it. The mod consist of putting a modified c90 drive unit on a c50 it lowers engine rpm for highway cruising. here is a pic of mine installed

http://i32.photobucket.com/albums/d11/johbren/IM000275.jpg

Thats cool! Always wanted my rmp's to go down while at highway speeds. Is this an expensive or difficult job?

here is the web site where you can order yur drive
http://www.djsllconline.com/

hmmm 400-500 bucks. did you notice much ofa mpg gain? Seems simple to install too.

I havent had enough ride time on it yet but from those who have they report around a 10% gain in gas milage

It's been a couple of months since you installed your DJ Drive mod. I was wondering if you have had any problems with it and what's your mpg now?

Ive put around 700 miles on the drive so far and it has performed flawlessly. If you go over to the volusia riders forum you can get a lot of info on the DJ drive unit. It really makes this bike sweet to ride. Gas mileage has increased a couple of miles per gallon in fact my last fill up was 59.5 mpg. Im doing a ten tank fuel mileage check and im only on the fourth tank so we will see. as of the fourth tank the average was 54.9