I have been reading the stats and it would appear that the mpg is the same for both the 330 and the 325 despite the 40 bhp difference, I'm interested to know if this is true?

There are several factors that go into fuel milage. Everything from tire pressure, tire type, the amount of weight you have in the vehicle and the days and times you drive it. Also consider the fact that the stats are only estimates. Both cars will give you similar milage if you drive them normally. But if you were doing hard fast acceleration where that 40HP difference will be noticeable, at that point fuel milage does not even matter. You are usually getting less than one mile to the gallon when doing a 12-second quarter mile.

You probably don't drive it as hard, because you don't really need to, so saving on fuel.

The 330d is even better, 45mpg and sub 8 sec 0-60.

The Mpg might be different by about .01 or .02 so according to me yes this is true