UK 2000 swap to 6S- need help
 

First of all, I am new here, so hello all :)

Now to the question at hand.
I have a 2000 UK WRX. (I am in Australia, and here they are called WRX's). its a GF8, and has the bog standard 8S ECU. I have been contemplating upgrading it to a 6S from an STI for some time, and have just taken the plunge and ordered one.
I have also ordered some 440cc injectors to go with it, since the 2000 uses 380cc injectors.
my main question is, apart from the injectors and the ecu, as well as the issue of needing to swap the crank sensor wire etc, what else do I need to do/should do?
I will be installing a new Walbro, and catch can to help with the detonation issue, since this is a JDM ecu designed to run on 100 octane jap gas, and will be running it here in Australia on 98 octane pump gas (I believe in the states it is called 95 as you have a different RON system to us, but don't quote me on that)
I will also be turning the boost down from the standard 16psi to about 15. that will hopefully be enough to alleviate any detonation issues.
now, any help with ideas or recommendations would be helpful, but my main question is, do i NEED to replace the little TD04 with its bigger VF23 brother? I really love this little turbo, as it spools up really fast and makes the car very nice to drive around the streets and I do not mind sacrificing a somewhat substantial top end in order to keep that down low torque (that and I would like to save some of the money that would otherwise be spent on it).

The reason I ask, is because I know that upgrading to a BIGGER turbo on an ecu designed for a td04 has all sorts of leaning issues, issues with boost still running high at the top end when the map is bringing down the ratio, but is there any issue with going the other way?

also, would you say its necessary to replace the stock fuel system with a split rail parallel system?

Thanks in advance :)

Seems like a LOAD of hassle for very little gain.
If it had been my money i would have sent the 8S ECU to Enduring solutions and got the daughter board, and saved the hassle of swapping pins and worrying about the wrong tubros.
It also would mean you are future proofed for change of turbo or injectors in the future.

Why? Just why?

What year is your car my99/00 cars came with 440cc injectors

Exactly this ^^^
6s from an STI
STI has different injectors,turbo,cams,maf ect from the uk2000
A LOT of money needed,why not just spend £400 get ESL and the cable so you can remap the car.
As well as cam&crank sensor pins I believe the fuel pump pin will also need swapping.

8s ECU is from UK my97/98 afaik

thanks, I was unaware that tge engine internals themselves where any different to the v3 sti engine. I was under the impression it was just the injectors and turbo. il look into an esl. not a huge waste - the ecu was only $100.
cheers all.