I want to create some precise firewall rules involving internal source IP, destination IP, protocol and port numbers.  TIme of day and bandwidth shaping would be great too.

I realize that overtly my C2300 doesn't support this.  So I am thinking about putting a proper firewall between my C2300 and my Internet connection.

I facilitate that, I guess I'd meed to put my C2300 into Access Point mode?  I see in the description some features will no longer be available (QOS, Parental controls...)  Is there a list of exactly what features I will lose by switching to Access Point mode?

Any other options to consider for precise firewall rules?  I did see an article online about modifying the router's backup configuration to add rules, then re-applying it.  I would prefer something more elegant like legit changes to a proper firewall product.  But I suppose I could do that.