ok, well as subzero33 has mentioned splitfires wont be necessary for you UNLESS you are having problems with your coils atm. If you want a new ecu then an Apexi PFC will probably be your best avenue (buy one soon Apexi Japan has filed for bankrupty and PFC have ceased production), however you would be able to get away with something along the lines of the SAFC you already have. Your turbo selection will be critical but you wont want anything too big as you want usable power, so something along the lines of a 25/30 would probably be fine. There are countless numbers of turbo companies who make turbos of this size including, HKS, Trust (greddy), Apexi etc. (Garrett make the turbo housings for a lot of these companies) the wheels are made by the actual companies. You will be able to keep your standard manifold (possibly need an adaptor plate)As far as cams go, they would probably be unesessary because the turbo you'll run wont be too laggy. You will need injectors and probably a new fuel pump as mentioned. Get cam gears so you can adjust the your timing. You'll need a boost controller (if you get a PFC you'll buy the boost kit, if not) any decent electronic one will do.
Basicly you don't need a lot to get to 250rwkw and with your torque worries if you dont get a huge turbo with mass lag it wont matter as you'll be on boost before you know it.