Hey Truck, thier were issues with the lower intakes, but if it has been replaced since 2003 it should have the improved gaskets.
Which this can be the casuse of head gasket blow outs.
My SE has had 5-6 intake gaskets, before I got the new ones. Its Moded a little

I run the DS out of it now, and I dont have any problems, but I keep up on preventative maintenance and run full sythetic on everything.
The earlier models of GA 99-02 had alot of problems with the passlock system/ignition switchs. Some leak water and damage the fuse boxes and blow BCM.
IMO i think $8900 is to high, but I guess this dependss on where you live. I;d at least try and get them down to $7900-8000 and throw in a warrnty.
Also ask them for the warrnty repair history , so you'll know whats been going on before you bought it.
Good Luck!