You can get close to 24mpg with a properly tuned CIS and a few mods but that is a different topic.
I was just wondering where the information came from that shows a difference in power output along with mileage for the Euro 930s. All I have read states the Euros were basically unchanged from '80 to '85, putting out 300HP.
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8