Both Saturday and Sunday are good days for both the racing and the airshow stuff, but Thursday is probably one of the best days for general walking around and watching the races themselves. The slower Unlimiteds, such as the Wildcat, P-40s, etc., all race on Thursday, so that's kind cool to watch.
I'm not sure where the best seats are anymore, but I can tell you that if you don't purchase a pit pass, then you might as well not even go. To me, the pit experience is worth whatever it is they charge to go there. You can literally be within a few feet of every airplane that races out there, watching the crews work, and asking them any question you wish. My experience has always been that people will generally be open and willing to talk with you, unless of course, they're working on a Merlin....they'll just be too busy to do anything else.
Either way, I hope you go, I hope you get a pit pass, and I hope you have a great time.
Gary
, there are no speakers in that area(thank goodness) I too would suggest getting a reserved grandstand up high so as to shoot good video and that way you don't have people heads in your way or they duck but too late 
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And of course you could schlep a chair in and tie it to the fence like a lot of people do, that way NO ONE 
