I want to keep the stock head unit and install an amp with new speakers I just want to know if anyone has done this .

 

Many have done this. You can get a simple loc unit witch jst uses the signal from your speaker wire. http://www.crutchfieldadvisor.com/IS...ps.html?page=4 You can also jst get an amp with a high level input and you dont have to buy anything. There are also a few that flatten the eq and give you better sound quality. Its up to you and how much you wanna spend.

 

If you select an amplifier with differential balanced inputs, you don't need to use nasty LOC's to connect the amp directly to the deck. Unless you spend alot of money on them, LOC's typically use transformers that have no business in audio. Here are examples of amplifiers with the proper input section to accomplish this task: Amplifiers