I just treated my 2011 with 66000 miles on it to a fill up with 11 ozs of XPD. What a change, engine is quieter almost immediately. Don't know about mileage yet I had an average of 20.6 for the last 10k miles. A lot of +75 mph driving.

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M DREI und M FUNF at ElkHart Lake

Current Fleet
13 C63 AMG. Sept. ED Delivery
12 K1600 GT
11 X5d (X Funf) ? PDC Delivery
10 C300 4Matic ED Delivery
06 M5 (M FUNF) ED Delivery
05 E500 4Matic ED Delivery
01 M3 (M DREI) Sons Daily Driver
01 Honda RC51 Sons Bike
99 Ducati ST 2 My Bike
95 Suburban 2500 Heavy Duty Mule
67 Mini Cooper S Just Makes You Grin
60 Triumph TR 3 - Sons
60 Truimph TR 3 - My college Car