I am interested in the idea of your install in the MR2, it's smaller size presents a great challenge to think outside the box with integrating a system that will give the ouput you are looking for. I would have to agree with the comments above about the Jensen HU. Really suprised that the Sundown Audio E8v2 was not suggested. With only 4.25" mounting depth it seems it would make it a possibility and with 2 of them it would have you in the power range of what the Draconia 4 channel could supply when the 2 rear channels are bridged. As far as the 4 channel amp, I would love to try one of the Zed amps. They have awesome looks and most of what I have heard sound promising. If you are tring to save a few bucks the SAX-100.4 would probly work for what you are trying to accomplish. Watts09 just put together a system on a 100.4 and he seems very happy with the results. Nice thing about using a 4 channel for your amp you should be able to get away with using stock alt., just upgrade bat and do the Big3 and you should be golden. Will be watching to see were your install goes! GL