I'm wanting to put in a new head unit it my 2003 grand prix SE. Nothing too fancy, but I have a few questions...I have never had a double din, and it looks like a double din would be a bit too big. Is a double din too big? I'm sure I can fit a single din with a little cubby underneath in the installation kit. My brother in law put a double din in his 07 grand prix. Looks like it doesn't quite fit. Second question...what special adapters are required? I'm guessing I have to bypass the oem anti theft? Third question...what are the advantages of a double din vs single din?