I want to keep the stock head unit speakers and sub, but I want to upgrade the amp so it hits just a little harder. What amp and loc would best suit this setup?

 

easy answer is its not going to happen

well i take that back. when you say hits a little harder are you looking for more bass?

 

Disconnect your stock sub from the stock amp and install a small aftermarket amp, something with 100 watt rms or so at 2 or 4 ohm, and that should give it way more bump compare to stock sound. Also if you want more volume and clarity from you tweeters simply swap your stock ones for some infinity reference 1031t at 2 ohms and prepare to be amazed. Tweeter leave with stock amp just swap out the speakers.

 

How well did the tweeters fit into the stock mount?

 

they dont but you could make them work. depending on the hardware u get you would probably have to glue them in or cut a hole in the sail and mount them that way

 

The package comes with about 3 different mounting brackets, I modified one and was able to use the stock mounting holes. But overall pretty easy and the best 20 - 30 bucks I've spend on my cobalt.