im running a series 2 grs with single kenlowe fan it fits near enough straight in but i had to chop a little bit of the front panel for the fan.
one of my mates is running a series 1 grs with twin fans dont think he had to cut any out but im not sure the problem is on a series 1 the fans mount infront of the cooler where as on most series 2 turbos they go inbetween the rad and cooler.

ill try and get some pics of mine have to steal my bros digital camera first though