I have an hmf full system, kn, 20 air holes in my air box. I'm looking to pull off the slip on portion of the hmf and purchase a pipe from the hardware store and clamp it on to the header so it will completely straight and no restriciton. Is it worth it? Performance gains good or bad?

 

Well straight pipes for the raptor werent all that impressive, case in point the fact that no one seems to be using them today. I dont think you'd see much of a performance gain, just a lot of noise. I say do some engine work if you really want power.