I went with an Alpine PDX-5 unit because I wanted a unit that would fit in the existing amp space. I remember coming across an article that gave the max dimensions for a replacement amp to fit in the slot (something like 12.#" x 8.#" x 2.#"), and there wasn't alot of options. This unit came the closest, so I'm hoping to retrofit the existing amp bracket without having to do too much customization.

I want to replace out the factory subwoofer as well, so I went with the 5 channel amp for the subwoofer later. I didn't want to have to wire a second amp for the sub. While I like having good sound, I also wanted a simple setup/install option as well.