In the any%, hero%, and villain% categories, extras are not allowed. Would it be acceptable to change that rule to allow extras as long as they are bought within the run? you could even make it a new category.

Extras are allowed in any% as long as they are collected and purchased during the run. They are not allowed in villain% because theoretically someone could stud farm before the run so they can afford an extra. But then if extras were allowed to be purchased during villain% runs, then setting up a new file to run on would take too long (all hero levels need to be completed before villain levels can be played). Since hero% and villain% are very similar in style, we've banned the use of extras in hero%.