I agree with those who have said that any DSM can handle quilting. Going through 2 layers of cotton and a layer of batting is nothing compared to sewing Jeans! The quilting in FMQ has more to do with your ability. When you practise a lot, your motion becomes smoother and more intuitive. When your motion is smoother, your stitches look better.
Personally, I wouldn't succumb to the pressure of your "same day sale" deal. There is always another sale, and there is always another deal. $800 is a lot of money, and I think your dealer can come up with just as good a deal later after you've had time to decide what you want to do. Whether you buy it today or next month, they'll still make a profit on it so do what is best to you. IMHO