Re-oiling was a process that I was not going to screw around with as there are rumors flying around about too much oil can kill your MAF (mass air flow) sensor. So I did a two-step process, from the bottom of the filter (the side that faces down in the air box) I lightly oiled the filter and let it sit on a fan for about 30 mins. Then flipped the filter over and let it sit for another 30 mins. This is to allow the oil to evenly be absorbed or wicked throughout the filter. An hour later I re-oiled any spots that didn't have the same color consistence. Meaning, spots that looked more pink then that cherry wood red needed some attention. Again I placed it on the fan but let each side "dry", if you want to call it that. So hopefully this excessive amount of "drying" would prevent any one area of being over oiled... The instructions say only 20 mins period of drying post-oil, but come on, MAF sensors are expensive.
So finally wipe down the rubber seal air the filter to make it didn't have any oil on it and re-install back in the S4. I should add I cleaned the inside and out of the air box as well… no point in putting a clean filter in a dirty box. Then took the family for a sun trip up to Deception Pass here in Washing, which is about 100+ miles. Honestly, I can't really feel any difference with the clean vs. dirty filter. Maybe a little less turbo lag, but no "holy crap this is amazing" moments happened. Maybe MPG went up by 0.5-1mpg on the trip. I think next week just to be on the safe side I'm going to remove the MAF sensor and spray it down with some MAF sensor cleaner. Anyway, hope you all are having a great summer!