Well, the TB likes to get carboned up and cause strange idling/driveability issues. Simple fix by just removing it and cleaning it till it shines like new. I don't know if the "tapshift" option was avail. on those GT's, but that was known to be an issue at times, and a replacement tranny for the tapshift equipped cars is more expensive than the non-equipped versions.
Besides that, the LIM gaskets may need to be changed out to the updated aluminum ones. Sometime in mid 04 GM installed the new ones, but there is no set date that indicates what car got what set. I guess they were using the leftover plastic ones until they ran out. Take a look on the pass. side of the motor where the LIM meets the heads and see if you see black plastic, or a dull aluminum surface between them. If black, then sooner or later you will be replacing them.
Front wheel bearings can be common. Always replace them with Timkin brand hubs. This can also cause the ABS/Trac Off lights to appear on the dash.
Other than that these are solid cars and can be driven well past 100K w/o issue. And even then often all they need is new plugs and wires (do NOT used platinum plugs in these motors) and they are as good as new.
