I've got a 5.4 and would like to let 'er breath a little easier . I have a cold air intake priced around $300+ or a filter for $30 . I can gain about 10.9 hp with the cai . No hp rating available for filter alone. My question is should I go with a complete cai or just a filter swap. Will I see a big difference in hp ,mileage between one or the other.