Those T-38s are small single engine jet trainers with no afterburners (I believe). While they will most likely make the pass at a similar speed and altitide as the Navy game last year, they should not make nearly as much noise as the F-18s. Those guys were coming in hot anyway, and I'm pretty sure they lit the afterburners right as they got to the stadium.
I cannot remember the specifics, but I remember reading a newspaper article about a year ago that oulined the costs of a 4 plane F-18 flyover for either a Patriots game or a NASCAR race and it exceeded $100,000 (mostly for fuel if I remember correctly). I can't remember what it said about who actually paid the bill.
I attended the Armed Services Bowl in Ft. Worth 2 years ago (Air Foce versus Cal) and they came by with an F-22 Raptor, a B-1 Bomber and something else and it was hellaciously loud (in a good way). You see those guys coming in at high subsonic speed and low altitude it makes you glad to know they are on our side.