i had upgraded from stock to Polk db690's. Had no real low end. When i added my subs i spent the money for some good components, well worth the money. They still surprise me with their sound quality even after a year.

 

I had Alpine Type "S" speakers in my 2003 2500 and didn't have any problems with fitment. I had them connected to an Alpine head unit and they sounded excellent! I have been a fan and used Alpine for the last 9 years... I can't say I had one complaint. Check out crutchfiled's website for mounting depth and sizes so you know what fits and what doesn't.