DBD or Arneson drive anyone had one?

Im currently finding another Trim Cylinder for my TRS drive they are about $900:-[ so i have looked at the Arneson 1721 drop box and the DBD drive does any one have any first hand experience with them?
just some Pros&cons and also how will they fit to my velvet drive will it bolt strait up ???

Alternativly can i run another type of cylinder that dosent cost the earth. My view is if im going to pay $900 for a cylinder i may as well sell the TRS and buy the Arneson 1721 drop box for $2500 and enjoy the extra speed and fuel savings.

http://img163.imageshack.us/img163/9329/dscf0212h.jpg