The wiring for the starter and oil pressure switch come off the main loom where it runs along the passenger side chassis leg.

I Put the same racetec oil pressure gauge in mine, you need an adaptor that screws into the engine block then the racetech pressure sender and the original pressure switch fit into the adaptor so both can be used, you can get all the bits you need from Burton Power or might be able to pick them up cheaper on Ebay.
http://www.burtonpow...t=40&q=racetech

The two lights at the back that come on as soon as the ignition is switched on - are these the brake lights, the pedal switch could be knackered or need adjustment.
This is info i got of another site.
The wires are on the passeger side chassis leg.
I will have a better look at the weekend .
I have looked but without any luck so far.