IF you have money to burn....I am sure their will be after market devices for the 6.4 as there is for all the rest of the diesels....IT IS ILLEGAL TO REMOVE THE KAT AND PARTICULATE FILTER. AS OF JAN 1ST 08. now that being said...you can remove em and stay out of prison...but...if your less than a NASA engineer you will never figure out how to make em run if you do remove the cat and particulate filter. They are not like the older catilysts. Everything is tied together. I READ......go to california dept. of licensing/smog control. IF you can't pass the tests starting in JAN 07......your dirvers license will suddenly dissapear....GOD DAMN...HITLER MUST BE IN CHARGE.