Hi Johnny,
I've got the same issues, I've just ordered the twin fans from finishline to supplement the two 12" fans I've got behind the rad. I'll let you know if it improves things. I have 100 deg c in slow traffic up to 110 if stationary.
Another thing I saw was an electric water pump in addition to the mechanical to keep the flow up at idle;
The Davies Craig EWP115 electric water pump from MAW Solutions Ltd
Mark