my 2011 e350 is due for 60k mile service that includes spark plugs. i received a quote for $1318 total, i asked the SA to run the numbers on prepaid 3 pak and he came back with $1903 total for next 3 B-A-B services. is this a current price of the 3 pak he told me the pricing comes from MB and its not negotiable. btw im in chicago everything is expensive over here.