I just recently purchased an 04 limited equiped similar to yours. I have been looking into lifting mine ( which is equiped with X-REAS and rear air suspension )
Looking at 4route's well documented revtek install and a quick look at the rear of my limited, I would agree that it looks like the spacers would interfere with the air lines.
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In the July issue of "Four Wheeler" They have and article entitled "Project TraiLex part I: We told you so..."
(
http://www.fourwheeler.com/projectbuild/129_0407_lexus/ )
In this article they are preparing a Lexus GX470 for the Rubicon trail. Their solution for lifting the GX470 was:
"Here is our 3-inch front lift kit. The stock Lexus front coilover shocks feature adjustable damping and are easily up to controlling 33-inch tires. Stock tires measure 30.5. The bottom mounting eye is part of a 2-inch-long, 5/8-inch-diameter shaft that extends to the shock body. We simply cut the shaft in two, did some careful measuring, and then machined a 21/4-inch spacer which press fit into the two stubs. We then welded the assembly into a solid piece and voila!, 3 inches of lift at the axle hub. The rear lift is already built in with the GX470's air-ride rear suspension, which, on its "high" setting, lifts the vehicle 3 inches. With our 3-inch front lift, the rig sits level and fits 33s with no problem."
In this article they don't have any real information on how they did this "modification" to the rear, just the fact that they did it.
I am positive I don't care for the method they used on the front, I am still thinking about the method that they used for the rear.
jlb
(correctly attributed spacer installation documentation)