Was there ever a recall on these??

There is, unless your vehicle has more than X number of miles on it when the recall was initiated. Then, your probably SOL. Best thing to do is call your local MB service center, and give them your VIN, and have them find out if the campaign is still open on your car, or if it was ever opened in the first place. And see if there's any way for them to cover it.

i believe that cats are legally required to be covered at MB's expense for 8 years or 80,000 miles.

Have a bimmer and cats were always getting fried. Got the cats replaced by BMW; no cost to me.

for what it's worth...