Hello,
I recently got my hands on a 2004 LeSabre. I want to build something different and I have a soft spot for the 3800. I want to firm up the suspension, which seems to be a common issue. I've seen so many different opinions that I'm more confused now than when I started. What stood out was the Bonneville GXP (?) for its performance suspension. Found Moog front springs specific to this application, so I'd imagine I can find the rest (junkyards near me are useless). My question is, will the entire GXP suspension (springs, shocks/struts, sway bars) or its aftermarket replacements bolt up? I'll be using poly bushings where possible. Are there other applications that will give me a firmer ride and get rid of the body roll?

Since they are both "H" cars, should be plug and play....

Yes, installing front springs, sway bar, and front struts, will stiffen up the front.....

But I think your rears have air struts.....those should be replaced with regular struts(stiffer, the better), with new rear coils........this means disabling the compressor, etc.

I remember one time a customer came in complaining of a stiff ride on his Lesabre.....he just bought the car used....he previously owned a LeSabre, and liked the "tah-tah" ride......his rear struts were recently replaced by previous owner......bough OEM struts, and he had his floating ride again....

I like the mushy ride in a Lesabre.....it fits the style of the car....you should have bought a Bonneveille in the first place...if you like a harder ride, more sporty interior/exterior.....one of my favorite cars....

I actually decided on the LeSabre BECAUSE it doesn't have a sporty look and it has that old man reputation. Nobody will see it coming until I blow their doors off. Probably should have mentioned that I want the ultimate sleeper. Besides, I got it for $500 with a fresh inspection sticker and didn't have to touch it beyond a tune-up. Perfect starting point for a low-key Camaro killer. Not sure about that FE5 suspension though. After I found the springs, nothing. Finding plenty of pieces for an F41 Park Avenue though. Maybe not quite as sporty, but I think it'll still tighten things up quite nicely...

Rethinking this, Bonnevilles had the stiffer suspension and they did use rear air struts.....

Does the LeSabre have a SC'er?

Not yet, but it will. Just haven't decided whether I'll get the ZZP blower for the N/A engine or just go all out and swap to an L67. Already have the parts to upgrade the tranny...

Do you have a tuner? Simply slapping a supercharger on a L36 isn't plug n play. Neither are canned tunes.

I don't have anything yet. Just got this girl a few days ago. But if I go with the ZZP blower, they flash my computer as part of the package. If I go for a full swap, I already know I need the computer. I'm good under the hood, for the most part. But swapping suspensions, especially between different models, confuses the hell out of me. Unfortunately, there aren't any dyno shops around here. I'd have to go into Ohio or Virginia for that if the PCM flash doesn't do it...

Looking at Rockauto, the OEM struts (ACDelco 506254) are the same between the 2004 LeSabre and the Bonneville 4.6 .

For the rear suspension, the same OEM shocks are listed for both the LeSabre and the Bonneville (ACDelco 504146 or 504147), except for the Bonneville FE5 suspension which gets ACDelco 540643 . All of these are air shocks.

I suspect the ride firmness has a lot more to do with the springs than the struts and shocks.

Hmmmm. If that'* the case, then I think those Moog springs just may work. With the shocks and struts, anyway. Would it matter that the sway bars are from an F41? I haven't seen a single FE5 sway bar, and I was looking for the better part of the morning. This seems too easy for a car with no aftermarket...

And now that you reminded me of Rock auto, it looks like they have the front and rear springs for the GXP. Both Moog and ACDelco…