I want to remove the catīs of my 2004 4.6 mustang GT, what is better to get more HP and torque an "H" pipe or "X" pipe ?? I also going to install a cat back !!
Thankīs !!

 

IMO I don't think there is that big a difference with hp or tq gains between X or H the difference is so small that ou will barely notice it , the most difference you will notice is the sound with the H pipe you will get a more muscle car sound then you will with the X pipe.

 

X pipes make more power with cars that it'll make a difference on. Your's isn't one of them. Pick whatever sounds good to you and enjoy.