I think the current ruleset should be extended to prevent some abuse and give an even playing field for everyone.

Things I'd add:

• Can't use forzathon rewards (doing a speedrun during forzathon gives you like 700k credits after unlocking second festival)
• Can't use car tokens (microtransactions to upgrade cars for free)
• Can't use tune/design rewards (if you have a public tune/design on a previous save, you can still collect a credit reward from it during the speedrun)
• Can't use VIP membership (doubles wheelspin credits)
• Can't use auction house (Has heavily discounted cars that are random for everyone)

Also anyone who doesn't own blizzard mountain or hot wheels has to watch unskippable cutscenes for them during the speedrun that wastes like 2 minutes (perhaps the time it takes to watch those could be removed from the final time)