As someone already stated go with the GMPP handling kit. The only thing you will not get with the GMPP handling kit is the trailing arms. They have been discontinued. UMI makes a set of trailing arms for the w-body that are tubular. Also, some have said that the GXP trailing arms are tubular and are the exact same part as the GMPP trailing arms.
As far as struts, you can use any strut that was offered on the 97-08 w-body. The spring is what will affect the ride height and not the strut. Your stock springs will work with all of these struts.
The GR2's are good for stock replacement springs. I would not recommend you use them for lowering springs. Mine were shot at just over 10K miles.
The AGX's are the next best adjustable strut to the discontinued GMPP koni's. Yes these will still eventually wear out but they can handle a lowering spring much better than the GR2's.
The bilsteins found on the GXP's are a very good strut. They will handle the a lowering spring just fine. These are what are referred to as the FE4 suspension.
The comp g springs have been said to be a little on the stiff side. I am not sure how well they handle a lowering spring. KYB also sells their version of the comp g's as the excel g. Here is the thread for the excel g's. These are referred to as the FE3 suspension.
http://www.grandprixforums.net/kyb-e...ech-45867.html
I recommend you use ant-pogo washers with any of these if you decide to use a lowering spring.
Originally Posted by The Guz
