Unfortunately, it seems a mess from removing the filter is a given. There is a small molded piece below it that is supposed to catch the oil and funnel it down, but mine still made a mess. Best advice I have is to put a bucket below before you remove the filter, at least the drips will avoid the garage floor.
6 quarts is correct. Synthetic isn't required, but I'm sure you can find numerous debates about it. If you are going to use the oil life monitor (7-10k miles between changes), I'd go synthetic. And use a good filter regardless.
Be sure and dispose of the oil properly. We wouldn't want a bunch of oil in the ground. Oh, wait, isn't that where it came from originally?
