Yes - precisely that. I could possibly fit an adjustable fuel regulator to help increase the fuel pressure, but it's unknown if that'll still provide enough adjustment. Much easier to go for a full standalone.
Info from the tuner so far (yet to pick the car up):
- Running rich at idle - factory ECU is constantly adjusting the IAC to keep the rpms low causing the idle to hunt.
- Running very lean up to 4,500rpm (pings when hot)
- Runs very rich from 4,500rpm up to 7,000rpm (black smoke out the exhaust)