if i replace my radio with an after market one will it fit it the slot that the stock ones in?

It should. You may need an adapter and maybe a wiring harness for a clean installation.

Try crutchfield.com They make a ton of adaptors for all makes and models of cars.

You need a special adapter because your AC controls are part of the radio. Metra makes one that you can get from places like crutchfield. It isn't bad for 05-07 but I would really look into getting the factory double din conversion. It's the adapter used for the japanese spec models which don't come with the stupid bose radio. It usually goes for around $200 but you can find them cheaper used. The quality is higher than the metra unit.

Infinitis aren't good cars to put AM radios in! I say don't do it! Send your broken one to this guy! I did this and my factory radio works now! http://www.ebay.com/itm/BOSE-INFINITI-G35-NISSAN-RADIO-6-CD- CHANGER-REPAIR-/250876872788

i have a 1998 chevy 1500 silverado....after changing factory radio to aftermarket stereo i lost hea and ac