We have run 2h 45m races and 4h races with multiple classes. I've loved it and the only complaints I've heard had to do with the lack of announcing and track issues (temporary circuit so you pay your money and take your chances 8)).
Endurance racing is a blast. Equipment is what it is. We've seen cheap cars win and expensive stuff pull it off. The best part is new strategies, teammates, troubleshooting, team work, concentration for more than a sprint race, and on and on. People who don't participate are just scared of looking bad or just don't get it. Which is fine. To each their own. We joke about those "shelf-princesses" that won't get dirty or scratched. It's too bad because you should just use and enjoy your gear. When something breaks replace it or figure out how to fix it.
I've maintained 20 - 30 minutes out of our packs with 4200's being the longest lasting. If you run high-bite tracks that require little throttle control you will run through the packs a lot quicker. Track set up is everything for battery life. You'll never know until you run the first race and then everyone will be bench racing non-stop until the next show.
Run your race and have a good time. You will make some believers along the way and add to your email list of those to invite for the next race.
