I'd like to see that dual alternator setup! S&P makes the A/C bracket to mount it high on the passenger side head. Unless you're going with a front mount turbo that is the ideal place for it if you don't feel like chopping up the frame for the stock a/c mount location.

NelsonPerformance.com can build you a harness so you can place your PCM anywhere you want, even under the front seat. Just give them length of the wires you need from the PCM to a reference point such as the centerline of the block at the back of the engine. With their setup you only hook up three wires and they provide you with and ALDL connector that has the SES light built into it to simplify the installation. Give them the length of the wires from a reference point for where you want to mount the ALDL and they can compensate for that too.