hey, if it's not too late, look at this
http://aircooled.net/new-bin/viewpro...02200562746339
if you haven't done anyhting yet, i'd go with IRS for handling and ride comfort issues. you can use the sway bar to adjust the rear end, cheap and effectively. go with better adjustable suspension or stiffen your torsion bars.
plus, if you want to drive it on the street you can out handle people better with IRS