They're not that heavy but heavier than a lot of other forks, and no I probably wouldn't, they're better just for casual freeride, if you want to race I'd definitely get Boxxers instead.
everyone underestimates domains, just cause the dual crowns are heavy doesnt mean you cant race with them. I race my bike with a single crown domain 302 and it performs great, theres no reason you shouldnt be able to race with a fork just because its slightly heavier
Trust me dude, if you're actually into racing these do make the front end quite heavy, I would suggest Boxxers for racing, its just I don't race And single crowns are going to be a lot lighter than duallies