EDIT: The best answer selected was incorrect, a side fan will not fit. Just tried
I have an Antec 902 case with a Tuniq Tower 120 Extreme fan on the CPU, the clearance between the side panel where another fan would be installed and the Tuniq fan seems rather small. I wanted to install a blue LED fan simply for looks, but I'm worried about whether or not it will fit. Does anyone know how big the fan would be/whether or not it would fit? Thanks
It will work the Tuniq 120 Ex. is only 150mm tall leaving enough room for a side fan.
I have a 902 and a 160mm tall cpu cooler and was close to being able to use a side fan.
Close but no dice.
You'll be fine though.