Myself and wyotechmsa are doing this swap..here is some info from maximum motorsports...
As far as what is needed to install the IRS into your car, all of the necessary nuts, bolts, and brackets will be on the donor car. You will however have to do a little fab work since the IRS was never intended to be installed on pre-99 cars.
-The rear brake lines will need to be re-routed since they changed the lines with the body style in 1999.
-Also the rear IRS bracket bolts into a capture nut in the frame rails of 1999 and later cars. There is no provision for this bolt on your car. It is necessary to weld a crush-tube (similar to our panhard bar crush tube) and into the frame rail to accommodate for this bracket on all 1998 and older cars.
-Lastly, all 1999 and later cars, both solid axle and IRS, use a 14mm lower control arm bolt on the chassis side mount. You have two options here, you can either drill out the holes in the chassis side mount of your car to accommodate the larger bolt, or use our urethane subframe bushing kit ( MMIRSU-2) with a smaller 12mm crush sleeve for a direct bolt in.
here is a VERY helpful thread....
http://www.svtperformance.com/forums/showthread.php?t=391333&highlight=irs+swap
