I bought the Alpine KTP-445 to match with the Alpine CDE-HD137BT and a pair of Rockford-Fosgate Prime R1693 6x9's for the rear and a pair of Rockford-Fosgate Prime R164 6 1/2" for the front. The speaker installation was fairly simple, requiring minor modifications. The Head-Unit and KTP-445 was a piece of cake to install. As soon as I turned it on, I fell in love with the great sound. Even using Rockford-Fosgates lower end speakers, the Bass, Mids and Treble was superb. For the little amount I have invested, this system sounds much better than the High-End $1500 system with huge Amp and Sub I have installed in my truck.
The KTP-445 is made for newer Alpine head units, is way easy to find a home to hide it in and there are no huge power cables to install. Simply plug it in to the head unit, then plug in your existing car wiring harness and you're good to go. The 40 watt RMS it puts out drives my speakers like there is no tomorrow. I am extremely happy with the performance. I think the creation of the mini-Amp will undoubtedly be the demise of the huge power robbing amps of yesterday. This KTP-445 is the beginning of the new future for automotive amps. Technology has finally happened upon the automotive world. If a new sound system is in your future, check this Alpine Amp out. You will not be disappointed at all. My new system in my car proves you don't have to spend hundreds, if not thousands of dollars to create that system everyone will be envious over. Alpine also make this amp for systems other than Alpine, the KTP-445U (for Universal).