If you keep those pressures you will find the tyres wear more on the inner and outer sides of the tread. It may not seem much, but over the life of the tyre it will make quite a difference.
Chris, it will look fine with the ducktail or even the Sportivo one. I'm actually keen to see a ducktail only setup, don't think I have seen it done before.
Technically you do not have to have a spare in the car for a roadworthy, however, if you do it must be in a roadworthy condition. The spare still must be the same overall rolling diameter as Mick said.
See if you can trace the wiring loom from the clip in plug on the alternator and check for any damage. Also check connections for corrosion and broken/damaged pins.
ECU's will "learn" driving styles, however while you may get a little more response, it really won't be that much and certainly will not gain any worthwhile figures on the dyno.
There is one in Brisbane that is possibly the fastest in Aus, puts down 200kW at the wheels. Pretty damn clean too, belongs to a mate of mine, sadly he hasn't put many pics up of it.