KTP-445 - Alpine 4-Channel Head Unit Power Pack Amplifier
I didn't want to spend hundreds of dollars on a huge amp to sit in my trunk. I got this thing and it powers my 4 mids and 4 tweeters perfectly all while sitting hidden behind my dash.    This unit is installed in my '02 Passat with an Alpine CDA-105 receiver Alpine KCE-400BT blue-tooth adapter and 2 sets of Polk db6501's.    Pros:  + Just the right amount of power  + Low price comparatively    Cons:  - If I decide to get a subwoofer, I will need a real amp