I've been led to believe that the installation of a cone filter can actually be detrimental to an engines performance, resulting in up to a 5bhp loss in power. Is smoothing the stock air box is a better option? When I refer to a cone filter, I mean the kits that sit in the engine bay as oppose to a cold intake system with the filter located down at the the bumper. Would be interesting to here peoples opinions and personal experiences of this and whether it really is the case. BTW, I've got a 1998 1.8T, 150, AGU (which will be remapped as of next week, can't bloody wait!!).