In stock configuration, my '02 BA used to get 44-45 mpg. But, as is the case with most of us, I had 'the need for speed.' So, after all my mods, I now get about 35 mpg. To put this in perspective: gas is about $2.50 per gallon. At the most, we might buy 4 gallons at a time. That's 10 bucks. The difference between 35 mpg and 45 mpg is 40 miles. The difference in cost is $10 (at 45 mpg) or $11.43 (35 mpg). The grin on my face with the increased performance is well worth that extra $1.43, at least to me, and I'd wager for most everyone else, too. My BA is currently in the shop getting the Weisco big bore treatment. If its as good as Dinqua claims, I don't care if I drop to 20 mpg!