http://www.passonperformance.com/images/stories/passon_documents/Passon_Overdrive_Flyer_20091109.pdf for the info, but in a nutshell, here's the good news

21% decrease in rpm in each gear
Stronger than the factory 4 speed
can be swapped into your 833 case with nothing more than a gasket set
$1800 for the kit, $3000 for a complete trans already converted

And you don't have to change anything on the car, not the shifter location, the trans tunnel, the driveshaft.. nothing needs any changes outside of the transmission