Well, an update in case anyone is curious.

The car cut out once on the way to the workshop tonight - wavey had to change ecu beside the roe hwy before it would start again.

Went and tested the new cam and crank sensors - didn't make a difference. Mikey had a scantool that we plugged in to the OBD port. How cool are those things?!

Apparently the intake air temp is -40C - will have to check the standard airbox and see if there is a temp sensor somewhere that we haven't reconnected.

The O2 sensor wasn't working, so we replaced that with a spare.

Car then stopped working. After a good few hours of scratching our heads, someone poked the ecu plug while it was running and killed the engine.

Lots of poking and prodding ensued, and it looks like there are a few dodgy connections on the ECU plugs. Can anyone suggest a source for an ecu harness I can hack apart to replace ours - before we leave for the rally tomorrow arvo?

Anyway, bodged that up for the time being, but the detonation problem is still there. I pinched off the wastegate bleed line, resulting in ~9psi of boost rather than the 14 or so it was previously getting but it didn't make a difference. What can cause detonation? Bad fuel, too much boost, and too much timing? Any way to check whether the knock sensor is working?

Two steps forward, one step back...