alright a quick question, the truck is an 05 silverado crew cab, no bose, no onstar, is there anything else besides a fit kit thing for the size if i get single din, because local shops keep telling me i need a wiring harness of some sort to keep my alarm? and the chims when the door is open. and i also believe one told me i need a harness for fm radio which i would like to keep, i would love to get a new deck but if i gotta get all these harnesses and stuff with a deck being 100+300 for harness and chims thats like 400$???