[rolltideroll]

I am very knowledgable in the area of car audio. I have owned a 2000 1500, 2002 2500HD Extended 6.0, 2004 2500HD 6.0, and my current duramax, so I have encountered all GM audio setups. There is a 6.5 component set (6.5in woofer and a tweeter) in most 2000 and up GMs, Extended cabs have a 4x6 in the rear, and crew cabs have a 5.25. You can easily fit a 6.5 though, which I like better. In the extended cab versions you can put either 2-8inch subs, 2-10 inch subs, or 2-12 inch subs.Downfiring boxes sond best. Probox makes the one of the best boxes, they make the most use of available air space which is the key to good clean bass. With any sub woofer set up you want to check the air space requirements of the subs to make sure they function properly. The probox also is covered in a bed liner like finish. If you have Bose in your truck and wanting to add subs-amp and are wanting to keep the factory radio, you will need a adapter to tap into the radio harness located under the front cup holders. There are several brands out there in the $60-$80 range. The factory radio is considered a din and 1/2, and there are not many good ones out there. A double will go in there but you will have to do some trimming and modifications to the mounting brackets. Feel free to ask any questions about products or installation as I can probably answer it.