If you ride in the national forest make sure the muffler has USFS approved on it. Some dont, even though they are a spark arrestor. They are illegal to use in nat. forest in the US. The muffler mod on here is very cheap or free, and is much quieter than aftermarket and almost the same power gain.

 

speedwerx has a slip on for your cat. as 400crasher said, watch out for non stamped/listed pipes. the speedwerx pipe is non listed/stamped so technically it is illeagel to the NFS. look at your stock pipe it should show a stamp stating it is NFS approved. my stock 05 400 pipe does not have that stamp. in some areas of colorado they are using a book of pipes to check against even if it has a stamp.

 

mod the stocker, sounds great and no packing to blow out if it gets wet. supertrapp mudslinger with a snork is only other real option besides hmf swamp for 650 (been told it will fit but might leak at the flange). speedwerx for a 400 will fall apart POS

 

I you want to use a HMF Slip on the one for the 650H1 will fit the 400. Thats what I'm using on mine.

 

I like the looks of the hmf slip on , but I like the price of the stock mod so I am trying to decide which way to go. Thanks for the info.