That last post is correct...that is the letter of the law....it also depends on where you live...if it is enforced...please show me the convictions of the folks that have done this...I am pretty certain based on the number of manufacturers producing these parts...there is little if any...
Do a Delete Kit...straight pipe and a tuner....your problems will be gone....more HP...better MPG...an NO DEF
There are plenty of threads on this subject...You Tube has a bunch of videos about it too...if you are mechanically inclined, you can do it all for less than $2000...
Unless you have an...