+1 to mdogg.
to further explination for some who want more of an understanding. the only thing a filter will hurt is the flow across the maf, it will not change its readings. now a different size maf housing that isn't the same as stock will cause different readings. for instance if your maf housing is smaller than stock you will run rich and if its larger you'll run lean. problem with some aftermarket intakes is they use larger than stock maf housings where as cobb and cp-e use the stock size. i also think fujita is close to stock as well. pipe bends will also have an affect on the reading because bends in certain places can cause turbulent air and that can skew the maf reading as well.