I don't miss an IndyCar or Formula 1 race and I also follow IMSA. Usually watch them on delay but do not miss them. Sadly, I had to miss IndyCar at RA this year but already have my campsite booked for next year. Buy a weekend ticket by end of October and it's only gonna cost you a Franklin. That's a bargain!
I have been to F1 races at Indy and COTA.