In regards to over/underclocking an AI's system... We have no idea if it's illegal. It probably isn't. Illegal and controlled substances tend to be more about controlling a product. changing the clock settings is not a product that can be controlled... It would be like trying to declare meditation illegal. Well, not that close but there's really not a lot of ways for humans to attain an altered state of consciousness without outside help. Momo's concern over May doing it at the party seemed more about her damaging herself than breaking the law. And seeing how scared May is about going back to Robot Jail, I doubt she would risk it just for a temporary high. Sure, some people do wind up breaking parole because of drugs, but that's people with an addiction problem. Something May has not been shown to have.
Getting repairs done by a friend/acquaintance would not be illegal. Especially if she's on record has having tried to get them through official channels and failing. Of course, there could be the old double standard trap... 'You can only get repairs through our authorized dealers. Our authorized dealers will not repair you. If you fail to keep your job because your chassis is falling apart, it violates your parole. We will not help you repair your chassis.' That's the kind of standard substandard assistance I expect when dealing with government agencies.
What we've seen so far there's no sign of that happening though, just that the parole agency can not/will not pay for repairs. So May should be okay going to someone else to have body work done. The sticky part is, she can't be associated with anything illegal. And May's already paranoid about even talking about the Robot Club. Maybe Faye and Bubbles can do some repair work on May outside of their job... but for storytelling sake that seems unlikely. Which puts May at risk and at the mercy of CORPSE WITCH and/or her parole agent... If he finds out, how he reacts depends on what kind of person he is. A by-the-books kind of guy would have to report the parole violation. A kind soul would turn a blind eye. An amoral opportunist would use this, something to hold over May to force her to do things for him, lest he report her.