ah64id wrote:
If the OP counts on 50% better mileage they will be disappointed. You are running a 5er, which are better on fuel than TT's. You are also talking 62-65, not 65. While that seems minor it isn't in the wind game with a TT.
Diesel is more efficient, no doubt, but I wouldn't ever tell anyone to count on a 50% increase in mileage. I would buy 40% better on a good day.
I'm curious as to why you think a fiver is better on fuel than a TT - surely a fiver presents a higher frontal surface area, which translates into more wind resistance? :h