I'm almost there converting my 2004 LeSabre to GXP suspension. Have some questions and a few issues though.

Rear shocks are in, front struts in. Sway bars waiting in the wings.
The front struts were built using parts from a 50k mile GXP, with the exception of the dust boots, and the strut cartridges, which were new GM parts.

I built both up, and the driver side has been fine. The passenger side has been giving me a lot of trouble though. I busted the original upper strut bearing after a couple 100 miles, and replaced with a new one (Monroe brand, from Advance Auto). Now, not even a week later, I can hear the spring turning on the upper spring seat. I haven't heard peep out of the other side, and all of this has been in for about a week and 1/2 now. The original passenger upper lasted a week before it completely failed. I've probably put 500 miles on the suspension since it went in.

Have any of you with the swap, or with a GXP replaced the upper strut bearing mounts? With what brand? I'm getting tired of rebuilding this thing. And the other side hasn't made so much as a squeak, and it has the original 50k mile upper.

And any advice on swapping out the front sway bar? I have new end links for it, but the FSM calls for pulling the exhaust, pulling the left tie rod end, and twisting it out that side. Is that the only way?
As far as the rear bar, mine didn't even have one to start with. (FE1). Anyone have a ball park size on the bolts for the bar to chassis mounts?

Thanks!

I've had great luck popping the lower ball joint on one side and sliding the bar out w/o dropping cradle or exhaust. By popping the BJ you get that little bit of strut movement that GM engineers and FSM writers couldn't perceive in their CAD designs.

On the mounts. You are assembling them properly with the bearing facing the proper way? A picture of one assembled would possibly help us determine if things are correct.

Bill, they are assembled the correct way. The driver side still has no issues. Its just the passenger side.
I'm just wondering if its because the Monroe mount is cheaper and can't take the stress of the FE5 spring....
I have 116k on the original FE1 struts, and they still turn fine, just the strut cartridges are completely worn out.
I think I may give it another shot, and order the Moog uppers and see how they work. The Monroe has a warranty, so at least I can take it back.
I've built up plenty of struts, for my cars, friends cars, etc. Its like doing an oil change at this point.
I was just curious to see if anyone else had issues with certain brands of upper mounts. Generally, I usually buy all Moog parts, but when the original upper died, all they had in stock was the Monroe. At least its not "popping" like it did when the original went out Somehow, this one is turning on the upper spring seat. Its not winding it up and popping like before.
It was together right. When I first put it in, I noticed a big difference in how easy it was to turn the wheels. Its just that it didn't last for very long.