Yup sunday is a pretty non-eventful day besides the burnout show in the afternoon. I've never yet stayed and watched all of the burnouts because its generally sooooo hot that after 2-3 days of it you just want to get home out of the heat.
I'm thinking this year I might just go down early sat and come back very late at night after the main showground show is over and save my money from sunday and buy the dvd instead, still unsure.