I am learning the hard way that to substantially improve the sound system over the infinity requires a healthy budget.
So far I've installed an Alpine 9886 ($300), Ipod/RCA cable ($30), harness, antenna adapter and fit kit ($45), Kenwood 4-ch x 75watt amp (marked way down to $150), Boston Acoustic SL60 components ($170), Alpine Type S's in the rear which I yanked becasuse they sounded terrible. Need to order different rear speakers still, so another $125 for SL65's. Plus wiring kits, speaker adapters, amp power wire, installation, etc.
Still need to spend around $200 to get my steering wheel buttons working with the new Alpine (newer trucks need not one but two interfaces!).
While it all sounds cleaner and my doors don't rattle when the volume is cranked, it's not yet substantially better than what I had. As poor as those infinity 6x9's are constructed, they actually do produce more bass than I have at the moment. I'm going to need to throw more money at it to get it right. I have a sub box from Supercrew and a new JL w3 sub to go in, but I'm losing interest in a hurry.
With the sub, I'm going to be around $1500, and I don't think I went over the top in any way. I was trying to get the best bang for my buck and I didn't achieve it yet. For the time being, I can run the sub bridged off the rear channels of my amp, but down the road I'll be looking to upgrade that as well. Maybe another $400 or $500?
Not trying to discourage anyone- just think you need to be realistic that good sound is going to cost some real money. I'm considering swapping back to factory at the moment as I really can't be throwing too much more money at this system.