I have to disagree slightly on the mirrors. The actual mirror is slightly adjustable, though he is correct in how well they work. I can use mine okay, but I've never riden another bike, so I have nothing to compare to. When you're running down the road, the viberations make it a little hard to make out what you're looking at in the mirrors and your arms will get in the way some.
As far as top speed, I've almost hit 80mph, but I was going downhill... And if you're going uphill, you'll lose a little speed. I'd call 70-75mph top speed. Comfortably, it'll do about 65mph.
And as far as the gas tank is concerned, Marc is right. It's a 20 liter tank which is 5.28 gallons. It does have a reserve and a gas gauge. I haven't check gas mileage yet, hope to get my first numbers this week. I'll post them when I get them. It seems that there is a broad window on the advertised MPG.