ECU Location

After moving the battery out of the passenger footwell I decided to fill the freed up space with the ECU.
I used two of the existing ECU brackets (one of which was chopped down a bit) to bolt the ECU to the bulkhead.
It's not exactly heavy, so two M8 bolts and nylocs should be ample!
I also stuck some self adhesive foam to the back of the ECU before I bolted it on.  It'll do bugger all vibration wise, but it made it 'sit' better.

 
The loom to the ECU is the original MX5 one, albeit heavily stripped and modified.
The bulk of the loom goes to the engine bay via a hole in the side of the tranny tunnel panel using one of the MX5 engine loom grommets to protect it.
The rest of the loom goes up into the scuttle where it will eventually connect to the fusebox, clocks, and pedal box.