I am thinking of buying a new Ford Racing Cobra intake($349) and a BBK 65 mm throttle body for my 89 5L.What kind of power increase will I get without getting new heads?I am looking for ultimately retaining street friendly power increases at a reasonable cost.I don't go to the track.The only mods I've done so far are all the chassis stiffening stuff,a K&N, Magnaflow catback and 3.55 gears.Is this intake worth getting?