I have got 50 at the most in one day but I think that you are punishing the honest people who go on the site. If you want to stop spamming the only way is to punish them directly and not everyone on the site. But that is only my opinion.
The con for this idea, is of course that it would discourage spammers
How is this a con again, Zophia? =P
The thing here is, even if you get this to work, they are still going to spam the same rate as they've always have. No idea, spammers would have 1,000 AP estimated. If the idea works, then the limit would be around 400 AP. The spammers would get up to 400, then keep going; it won't stop them from posting spam comments.
What we are doing is tackling the problem at a different angle. We need something, like we've talked about, like having the post button hidden until you post a somewhat-lengthy comment. I don't know who started the idea, but I'm following this one, and it seems to give a good start to Spam Stopping.
*wonders if kell read any of the previous responses*
@Shintetsu: Discouraging them is always a con. Eventually they are supposed to be discouraged enough to stop. That's why deletion and ban can be taken into use as well... All it really does, is discourage them. But I agree with you...
Seriously, why do people care about AP so much? It doesn't do anything. True, it makes people think your cool and all that, but really, if they want to earn 1000 AP a day, let them, it simply means they have too much time on their hands.