first mustang

[surfbeast]

You will never get to 290 with what you are doing, "sorry". You may get to 260 or so. A full exhaust change helps the most and pullies and cold air will help a little more. Don't believe the ratings on each bolt on product. If they say 15Hp gain that is with a car they are really tweaking to get that, remember they want to make money. Don't buy gimmiky stuff either. Your best bet to get to 290-300Hp is to do the head and intake swap for about $1,400 bucks from Mr. Wheeler. The cost of full exhaust,especially Borla and pullies etc will be about 3/4 the cost of the head swap.
Head swap = 65+ Hp gain Bolt-Ons/exhaust = 40MaxHp.
But you decide what way to go! The H and X pipe give ABOUT the samp Hp gain but in different places on the Torque curve and depending on what type of mufflers you use. Someone with exhaust expertise wil certainly chime in and let you know.

Good Luck and MOD ON!