scud08

I bought a flip screen cd/dvd player for my 08 Silverado LT. It does not have bose and is onstar capable although I dont use it (nor is it activated). I went to a car audio store and they told me I needed to buy $238 worth of install parts to put this in my truck. It's funny that they didnt ask if it had bose or onstar and went straight to the big bucks.

I have read that If I dont have onstar or bose, I can buy the 15$ install kit. My question is, I dont "have" onstar, but the truck is capable of using it. What harness and kit do I really need?

Thanks,
Scud