Yes, unlimited spending fosters the right to free speech, because it assures that individuals, both by themselves and collectively, can have their say. There is no limit to the extent to wish people can make speech in an attempt to influence their government. It is helpful people do not feel restricted when it comes to free speech.
Yes, unlimited spending does foster the right to free speech because it does not matter how much anyone spends, at the end of the day, everyone gets a vote and to decide who to vote for. It does not really matter how much someone spent on a campaign to get votes.