I thought this smallish tank would bother me, but it doesn't at all.
Sure, it's a bit smaller, and fill ups are a bit more often, but not really that much.
Even if it were 2 gallons more to be more typical of other similar cars, it would be like 16 gallons (my '06 A4 had a 16.6 gallon tank). At about 22mpg avg, that would only be 44 miles more before filling up again.
Not a big deal.
It's just that if you want power then you get less mpg, and along with the smaller tank, it seems to small.
For me, it just isn't an issue at all, and I thought it would be.
The little added benefit to this smaller tank is lower cost per fill up.
Granted, it's all the same, but it's nice to fill up and not pay as much as I was with my A4 2.0T. My A4 got better overall MPG, about 24-25mpg. But, it did MUCH better at highway runs where I'd see 30mpg avg. I can't seem to get that in my 135i at all.
But then, at highway speeds it's too fun and too tempting to dip heavy and often into that sweeeet turbo thrust.