i noticed today that my temp was running at around 98 when i was stuck in sit and go traffic. when i was able to open it up on the highway i was at 80. is this normal?

 

You'll be fine as long as the car is under around 100 degrees celsius.

From what I've noticed, the cooling system kicks in at around 80 degrees celsius. My w220 stands around at 90 fully warmed up, 80 on the really cold days.

98 sounds a bit hot, I've never gotten there, but 98 isn't anything to worry about. My w220 performs best at 90-93 though.