225/45/17 is 100% fine on a gc8 with the correct wheel offset, ride height and some mild guard rolling.   225/45/16 is 200% fine.

I'm also watching this with interest   

Some newer models have 18x7 or 18x7.5 so maybe tire option for those .      

True. Though a 215/40 is closer to stock rolling diameter than a 215/45 The biggest problem is finding quality 215/40 tyres. Back in the day one of the white GC8 wagon mob was running 205/40s on the track.  

IAC Resistance Middle Pin (12V Feed) to Either side pin = 8.8Ohms Right hand Pin to Left hand Pin = 18.6Ohms   Its weird because the check engine light comes on after coasting/decel, but now if i put my foot on the clutch and let the revs drop to idle the check engine light goes away and we are back to full power again   I put some CRC on the thing that sticks up after you remove the IAC Sensor and its super free / no jamming, i know there is a diaphram inside though maybe Its sticky or something, might just time to pull it off and give it a clean out    Installed a new fuel filter today just because they were only $35 and the one in their looked at least 10 years old