Hi, I would to know if it's really necessary to change my ecu if ever i wanted to have dp, mp, and 3" exhaust + air intake...

Can I just buy a boost controller to avoid boost creeps?

 

you could get away with all but mp.

 

ECU is a must with those mods.

 

I'm no expert on this seeing as my car is still stock.....

But I think opening up the intake and exhaust will increase the airflow through the engine, even with constant 10psi boost pressure. If you think about it, with less resistance to air flow, the turbos will have to push more air just to make the same 10psi.

All the boost controller will do is limit your boost pressure to 10psi, but you will still be pushing more air through, and more air means running lean, which means you'll be having your engine will be toast unless you compensate with extra fuel (thats where the ECU, fuel pump and injectors comes in to the equation)

 

with less resistance to air flow, the turbos will be worked less and spool faster. this is what causes spikes and creep. the turbos working too fast, and the waste gate cant keep up.

 

Another answer:
https://www.rx7club.com/3rd-gen-archives-73/stock-ecu-10-psi-myth-308996/