A:AnswerIt's the mounting parts that goes around it. Nothing else. You will still need to buy the wiring harness adapters separately.
Nice thing about this kit is that it does both single DIN and double DIN.
A:AnswerYes, that kit will work for your Tahoe. This should be the wiring harness you need, Metra 70-1858 Radio Wiring Harness For GM 88-05 Harness, as for the chime I'm not sure.