I dont know about your alarm, maybe it has backup power and when you reset ecu it will not erase power. To reset the ECU on r32 you disconnct battery, pump brake pedal a few times and then hold the brake on... then a few more pumps, then reconnect your battery. Check the forums though, there will be a how to thread.
For the spark plugs dont buy irridium ones. If you goto autobahn and tell them you have a non turbo rb25det and you want normal $2 plugs (NGK) you will get them, but if you tell them its a turbo they will sell you the $25 plugs which arent any better, they just last longer, but truth be said the cheap ones do a better job. Make sure you buy them already gapped to 0.8mm or get some feeler gauges and carefully gap them yourself.
Coilpack can be had for $485 brand new for 6 splitfire ones, they are a very well known brand. Or you could go with justjaps new range of JJR coils for $400... but persoanlly i just bought new coilpacks and went splitfires.. pay the $85 and get a product you know is tested and proven (no offence to JJR but its a new product, id rather let others test first)
For the parkers, check that they are actually there for a start too. And did the car come with a road worthy from the dealer... if it did then go back to them and tell them to fix the damm problem cause thats a dodgy roadworthy.
cheers mate, welcome to SAU