heating issue.. need opinions

No shroud can definitely make it overheat when idling at a stop. A shroud will create a vacuum (airflow) through the radiator by sealing the fan to it in essence. I have seen numerous cases where cars overheated without a shroud and when a shroud was installed the overheating problem was fixed. If it were a plugged up radiator or engine block it would overheat going down the road worse as rpm's increased.

I haven't used a shroud like the one in your link. You basically need a type that wraps completely around the fan to seal it to the radiator to work the best.

You also want to make sure the fan is at least 1/2" but not more than 1" away from the radiator and when you install a shroud you need at least 1/2" clearance all the way around between the fan and shroud.