Originally Posted by c32AMG-DTM

Yes, I believe the E55 TB to be 74mm stock - that's the whole premise behind why those guys spend the big bucks to upgrade to 80+mm when looking for max power/torque.

Some of the high-end 55 AMG's had 80mm TBs; maybe it was euro-spec, or an optional upgrade... I don't recall offhand. I do know that some SL55's had 'em, but not all - there are threads on MBW in the w211 E55 section that list the specific part #'s needed for the 80mm TB conversion; if you're looking to do this, they'd be a good resource.