I've seen the £300 (US$425) per corner Chinese (Airsusfat) air struts on eBay.
At that price I won't be converting from air when/if one of mine goes. :-)

 

Ya I've seen those too and wondered how good they are and their longevity. No one in the LS430 or LS460 threads has commented on them yet though.
There's also some oem remanufactured ones too that look interesting that cost a little more, like $550 each.

 

I have the exact same car with 354000kms. Bought it from original owner who had the fronts replaced under warranty at 100000kms and the rears at 180000kms. It was out of warranty for the rears, but because he bought this car for $112000 from them and he was a repeat Lexus customer, they split the cost for the rears.

I bought the car with 303000kms 2.5 years ago from him and the shocks are still working. Maybe a bit more bounce on normal setting than i like and the compressor will run every other morning to fill up the shocks, so i keep it on sport mode now and the ride IMO is better. If i do forgo the air shocks, i'm looking at using the Monroe QuickStruts that are no available for the LS430. Will just convert to springs and save myself the $6000 OEM price for new air shocks all around.

 

caddylover, I am in same situation, I tend to ride on "sport" mode more these days especially on local roads to keep car from feeling a bit... wallowy at times (2005 Ultra, 142k miles) . Do you have a 2001-2003? I see http://www.monroe.com/en-US/e-catalog/172341 for 2001-2006, but 172342 (rears) seem to show only for 2001-2003, so I fear they are not compatible. It also indicates "without Automatic Adjusting Suspension", but I guess you can install it on a car that IS the air suspension, you just you lose that (of course). I guess the mounting works whether existing car is air suspension or not?

I am always keeping an eye out for the best solution if/when day comes that I need to convert. My other concern is finding a non-dealer mechanic who could safely remove the back seat of an Ultra. I believe there is a lot (wiring, etc.) that could be screwed up if people will not take the time/knowledge to do it right (and I am not going to attempt it myself).

An alternative (pricier on parts) is Arnott. They do have front and rear, and are air-based (but not full OE functionality). Thoughts/knowledge on the Monroe's (rears especially) for 2004-2006?

 

the rear seats just pull up and you disconnect some wiring. IIRC, you can then access the mounting nuts for the rear shock. Alternatively, if you can find used OEM shock and spring set up, then just swap out the shock cartridge and you'll have a good set. Quick struts are easy to do as it's all assembled for you already. From what i know, you can use any shock from 2001-2006 as they are compatible.

 

I'll tell you about mine because it seems to be a bit of an outlier, but may be relevant. I bought mine with 98,500 miles and the air struts seemed like they were already starting to go out. Like yours, the rear would sit lower than the front, even with the difference in wheel well height accounted for. I had the shop confirm that the struts were weeping out their oils, but the bags seemed okay. This caused the rear end to be a bit bouncy over bigger bumps, and sort of numb feeling on the smaller ones, and caused bad wheel vibration over anything gravely or something like cobblestone. I rode on them for a good long while before eventually swapping out for KYB Struts and some RSR lowering springs. I noticed that with the lowering springs installed, the rear height was almost the same as it was before, with the front fitment matching much closer. Those two rear struts must have been on their last leg when I finally went to get them replaced.

From what I've seen in my time searching around about potential air strut replacements/rebuilds, it seems like they can last anywhere between 240,000km and 350,000kms+ with some variation, it seems like climate has to do a lot with it. Mine was a Florida car, and must have been parked near a glass sky scraper or something, as the grille and rear view mirrors are slightly melted?? Looks like they were hit with a magnifying glass. Im wondering if the heat, humidity and salty air (unless the car was deeper in-state) most likely contributed to it's shorter life-span.


I will say, unless you're very attached to it, to look into eventually converting it to coil springs once the time comes. With the KYB Struts and Lowering Springs, the ride quality is almost unchanged when it comes to gliding over smooth streets and absorbing bumps, however with the more aggressive spring rate and dampening you're able to feel more of the road. I personally feel like this is a good thing, as I feel more connected. Fret not though, as the classic Lexus glide is still ever present. Surprisingly, the body roll has been cut down by a huge factor and I feel much more confident throwing the car into a corner or just move with a bit more spirit without feeling like a wavering mattress. They do also make a few quickstrut kits, like the Suncore, and folks seem to like them, it's a lot less work when they're already assembled for you, I personally chose not to do it mostly because I wanted to take advantage of the situation to close the gap on the wheel well and I do not regret it a bit.