Well, since I've owned my 93 GS3 had a slight bit of vibration in the drivers seat when my car idled. For some reason I attributed it to the aftermarket exhaust Because of another members post on another Lexus forum about replacing his motor and tranny mounts. I decided to go ahead and do it. I have 115,000 miles, car still rides great, just a little vibration here and there, nothing to whine about. Well after pricing it out I choose to take it to my shop(Toyowest). I usually try to do everything myself, however, their prices are usually pretty decent and they do great work. So I bring it in for motor and tranny mounts. They just called to tell me the mounts are trashed, broken in half. However, they also found, when they lifted up the motor, a leaking dipstick O ring($120 parts and labor), leaking oil pressure sensor($235 parts and labor), leaking trans cooler lines($50). I had the tranny flushed 15,000 miles ago, needs to be flushed again!($169) I also mentioned a slight noise I heard occasionally that sounded like a bad drive belt tensioner, turns out the power steering pump is leaking from the shaft. because someone didn't change it frequently enough when it was new I changed it at 90,000, damage already done, should have been done at 15,000. Remanufactured power steering pump + labor ($400). As usual, I'm leaving paying close to $1000 Oh well, I'm glad I decided to do this, who knows how long or how much damage might have been caused.
The car never leaked on the ground, so there was no evidence it was leaking and I never noticed any leaking as all the areas were hidden from normal view. I did notice a little tranny fluid on the lower splash shield where the tranny hoses go in/out of the tranny cooler. However, after I wiped it up it seemed to have stopped leaking.
Everyone of the items being replaced are common failure items on the GS3's.