[MARTYMAR]

Originally Posted by AMS Performance

The different between 200-300 is almost negligible, however 200 cells can sound slightly raspier which is why I always opt for 300-cell metal core cats. make sure they are metal core cats (longer lasting).

There is no point in deleting the resonator honestly. Both the Resonator & muffler are AMG components and are a straight through free flowing design, whereas, the exhaust manifolds & cats are off the shelf standard mercedes components (and much more restrictive).

With performance headers & high flow 2nd cats installed you will really want to have that stock resonator in place because it helps clean up the sound significantly. In addition, from a more ethical/moral stand point, Keeping your secondary cats will help clean up the emissions more so than deleting them all together and its 100% legal to put in high flow cats, its 100% illegal to delete them so from that perspective the choice is quite obvious. Most high flows are at least 49-state legal, some are even 50-state legal.

Here are the cats recommend, they are 300-cell metal core cats. Price is $180 shipped for the pair (x2), simply email the seller & tell them you are from a mercedes forum and would like to purchase two for $180 shipped, they will accept. These exact cats made 10HP/12TQ @ wheels on NA 55 AMG on bone stock exhaust.

http://cgi.ebay.com/ebaymotors/High-...205|240%3A1318

(AMS has no affiliation with the cat seller, just a recommendation that's all).

Hope that helps,
~AMS~

I just sent an email to have 2 of these cats ordered hopefully by today! I'm also seriously considering the headers...