Sorry but a 86-88 Stang 5.0 was the fastest STOCK set-up out there. All your big time racers use Speed Density. Mass air just is more adaptable for the average Joe.
If you have a stock engine and don't plan on changing the cam, then yes that $40 set up will suit you fine and will be a direct bolt on since it wasn't HO.
As for ever body looking for HP, how many of you really run your engine to 6500 rpms? A stock set-up will do more than 3/4 of us will ever use on a trail.