My understanding is that the Financial Fairplay guidelines, such as they are, are largely concerned with players (transfer fees, wages and so on). So rich new owners can still make a big difference with regards to infrastructure and facilities, that sort of thing.
Our own experience suggests that it's good to be backed up by serious money, regardless of whether that money is actually spent or not. We can split hairs and argue over trophies or the need for fifty million pound strikers but at least we have good reason to believe we won't actually be going out of business any time soon.