Hi everyone, new boy here looking for information. Intend to be active here regularly, so thanks for letting me in

I have a 2000 Reg Impreza Turbo that started to overheat etc early this year.

I have sourced an RB5/Turbo 2000 for breaking with a good engine etc.

Do I need to also get the wiring harness for the ECU or will the wiring harness from my 2000 Impreza meet up with the RB5/PPP ECU the same way?

Likewise, I am also trying to purchase the exhaust system. Is this necessary to run the ECU or are there other exhausts on the market that will be compatible to provide best perfromance with the map and fuelling, back pressure etc required by the ECU I have done the deal for?
It has all the Prodrive extras from the WR Sport upgrade option.

My car has a Cobra alarm/immobiliser. I only have knew key, a very standard Subaru key, with the central locking on the immobiliser. I'm worried I may have to swap immobilisers from the RB5/Turbo GT series II as well as the ignition barrel and key.

I know these are a lot of questions, but I heard this is a great source of knowledge.

All help/assistance is greatly appreciated.

 

It's not clear whether you are doing a complete engine swap.... If the breaker RB5 has all the WR Sport upgrades, it will already have the required exhaust system, which is simply a decat centre section (either with a resonator or not, your choice) and a stainless back box, both available as aftermarket items. You will also need the upgraded turbo-to-intercooler y-pipe, which your RB5 presumably already has. The Prodrive ECU is plug and play on the '99-'00, a 2 minute direct swap, so no need to touch the wiring harness. The immobiliser/alarm is separate from the ECU.