I currently have a '97 MTX Thunder 2150 pushing a pair of '97 Kicker
Competition 12's in a '97 Dakota. Besides that everything is stock even
the head unit. I decided to upgrade the stereo but I had a budget to
stay in. I decided on this:

Pioneer DEH-2700 CD Receiver
2xSony XS-V1635X 6-1/2" 3-way speakers to replace stock rear speakers
2xAlpine Type-E SWE-1241
Sony XM-2200GTX 200W x 2 to push the Alpines

Right now I'm leaving in the stock front component set but am
considering replacing them with Polk Audio db6500 and adding a .5 farad
cap.

Keep in mind the Kickers are old and were the comps rated at 150w RMS
300w Peak. Will the new system be louder and/or better sounding than
the old system I'm replacing and by how much? I'm not planning on
competing or anything I just wanted to get a general upgrade in sound.

Also will it make a huge difference getting the Polks and the cap?

I figure just from technology getting better it should sound both
better and louder but I want an idea what to expect before I hook it
up. I have done a good bit of work on stereos in the past but haven't
touched them since about '98 so I'm not real up to date with the state
of the industry.

Thanks