the fans should either both be mounted on the rad and blowing in to it ( air into the engine bay) or both on the intercooler blowing through the intercooler onto the rad. if you wire the fans the wrong way round they will suck instead of blowing and this is to no advantage at all. simply the intercooler with the fans behind the intercooler (mounted directly to rad) are much better and thats why the later coolers all use this method. your standard intercooler dont have a fan so you dont need one on your new one, but your rad has a standard fan so you still need one when you fit an intercooler. They change them as the standard fan is very chunky and does not allow most intercoolers to fit over it.