Your max bid will have an effect on your ranking. Where QS ends and max bid begins is a gray area. QS can't be redeemed for cash, so it's tough to say how many cents per click a drop of QS is worth, or how much it costs to buy a good position with a lousy QS.
Your QS is also relative to your individual position. Google does not expect you to hold down a double-digit CTR if your ad is in position 8.