Be weary of that rear air suspension system on the GX, and keep a watchfull eye on the infamous driveshaft clunk. The self leveling rear air suspension, at times, when you come to a stop, will trigger the driveshaft clunk in a much more severe manner than in a 4runner with normal struts. Yes, the GX is the "limo luxury" of the 4runner frame, but the only reason why I won't buy one, is simply due to the fact that it has air suspension components. Once you've had any sort of problem with the system, your wallet will never let you buy another.
It's not so much the issue to fix the rear system, which "some" have problems with the system never turning off, or turning on when needed, but the fact that finding a Lexus dealership that will pinpoint the problem the first time, is next to impossibe. I don't care how nice the staff is to you, or how many free cookies you eat in the waiting "lounge", I have yet to not be taken on a wild (and extremely expensive) goose chase when trying to figure out a problem (usually a $50 part, which ends up costing $1,500 to fix).
I've had two Lexus vehicles, both sedans, both V8's (LS & GS). I've been a Lexus "guru" on another web-board for years. The #1 heartache issue on the vehicles....the air suspension. Rare will you find a fix for under $1,000 with the system. Heck, I think the struts themselves are north of $1,300 a piece. After facing the typical softening of suspension bushings in my 01' GS430 recently, I decided to not go down the Lexus Repair Rabbit Hole. At 60K original miles, I ditched it for a completely different vehicle. Until Lexus produces a service side of the house that doesn't operate under the "they're rich when they bought it, they're rich when they fix it" business model, I won't be buying another one, period. I can tell you stories of the wild bull**** stories I've faced in the Lexus repair shops that would make you think highly of Chevy.
They don't break very often, but when they do, they really hurt. I much prefer a $150 strut vs a $1,500 strut.
Additionally, it's not the miles that cause the repairs....it's the age, it's the soft rubber used in the suspension bushings and mounts (that give Lexus their famous uber' quiet and smooth rides) that eventually loose their composure. If you're looking at anything beyond 5 years of age, budget about $1,000 to replace a few key parts - Two engine mounts, one transmission mount, rear carrier bushings, and rear differential bushings.
