<< Sort of thinking about a programmable ecu now I have a decent laptop to meddle, but I dunno which ones will plug straight into my wiring loom, which are good/not good, easy to map etc. Plus the added factor that I'm not sure about paying the better part of a grand for an ECU on a car that's worth maybe only double that! It's all confusing. >>
You should be able to fit a Apexi Power FC dude, as your wiring loom is the same as the 92-96 WRX with 4 plug connector.
These can be bought for around £500. If you want someone to map it then Andy F is the guy for Power FC, but he's in Scotland. (Do you like haggis? lol)
He does scoobs for £700 supply, fit and map, I dont see how yours would be any different from mapping a 95 WRX.
Only prob is the Power FC has limited boost control, much more than standard boost requires the AVCR to work with the Power FC which adds about £200 to the bill.
But if your happy with your current boost and just want to sort the car out you should be fine without.
You can buy the software, but no idea how much or how easy it is to use. You can get the commander hand set for the Power FC though to fiddle with the settings in car.