CM - ZR6

I had the choice of two ex demo ZR6's both 2011 models and chose the one without sat nav and roof as it was cheaper and I really wasn't fused but like I said I was just curious as to why the difference!

Hello all, newbie here.... Just bought a 2011 ZR6 today which doesnt have Sat Nav or sunroof whereas some ZR6's of the same year do! Was wondering why some ZR6's have the roof and sat nav and others dont??? Im not too fussed by not having either of these but im just curious!