Yes there are SAE, STD, STP, ETC and DIN modes basically, and within SAE for example you have J607 and J1349 correction values.
Euros use DIN, we use SAE but should use different correction to 0° Detroit lab conditions to be honest!
I recently went to see the finished W310 package to see if it was worth the money. It looked nice, however I didn't think the exhaust sounded all that good. Personally I don't think it is worth anything what they are charging for it regardless of the nice sticker on the VCM OTR.