FAST FXI 2.0 EFI

I need to decide where to mount a FAST XFI ECU.  I don't want it in the hot engine compartment and am thinking on the fire wall behind the driver's seat, and mount an MSD ignition behind the passenger seat to separate them to avoid interference.

Suggestions and photos are appreciated.

I bought a FAST XFI harness and because of the longer and unnecessary wires, just bought their harness kit and will build a custom harness with minimum wire.  The harness kit did not include the larger wires from the battery and the FAST support said the two sizes are 12 and 14 gauge.  Does that sound right?  The wires don't look that big.

The FXI is for highly modified engine thus all the unused cables.

My engine is about 500 HP The PO had it mounted behind the driver's side seat and MSD on the engine side of the firewall on the passengers side.

It does not appear to be problematic

I've seen a lot of EFI installations do just that, install it behind the seat on the firewall on the passenger side.  It works and is what I did as well that way you can get various things connected including coil and ignition nearby.  The fast classic was kind of a bulky box but it still fits inside the firewall cover.  Due to my ECU being older, it only communicates with a Laptop.  The newer stuff come with touchscreen type controls to take the technical side of hooking up an existing laptop whether that is Macintosh or IBM compatible to the ECU out of the foray.  You need another level of expertise with some of the more advanced systems and most of these companies are trying to get the average joe into installing these kits and making them easier to take on.  Personally I just have a little mini asus notebook I use that is hidden in the car, and then I hid/mounted an Air Fuel Ratio Meter Gauge in the glove box that I leave open while tuning.  I wanted the interior to keep a relatively stock looking appearance.  The boy racer days are long gone for me   I'll see if I can get a video done by the end of the week.