The engine sucks a lot of air in. If the only air passage thru is the intercooler, that's where it will go thru; with or without the fan.
The "downside" is the argument where the ambiant air sucked in by the air filter is now hotter. I'd be curious to know the real difference of air flow through the intercooler with fan + non-blocked off shroud vs intercooler only with a blocked off shroud like Craig's.
87 930 K27HFS/B&B/Twin-Plug... Megasquirted