400ex HMF slip on hillclimb 

rzl07375 Yah I did notice a difference. Those inside welds are restrictive.

Darren Nelson thanks for the response. I have looked up lots about this mod. There is a lot varying results as some say they felt no difference and others said it reved faster but they lost torque.

rzl07375 yah I don't understand why some people would say that. After doing this with a hmf slip on, it performs what a full exhaust would.

Darren Nelson what did u gain the most, throttle response...I got an 04 all stock and doing some mods, thanks.

rzl07375 I noticed a increase in everything honestly. But I did slip on, filter and ground the welds, all at once. Made it pretty big difference vs stock. Really like to do a cam and port next to it.