Firmware Recommendations for whr-hp-ag108

Hello I have some questions.
We are about 10-20 persons that should share on one
Internet connection.
at the internet connection we should have this buffalo whr-hp-ag108.
we should also have it as client.
So what firmware should we use.
what we need for future is.

1. QOS/bandwidth management so we can set so no one can download faster than 2mbit and upload 512kbit. must be possible to set it for each port.

2. Client isolation or multi SSID.

3. VPN so everyone can use one VPN tunnel.

4. this is not a must be it would be nice.
Radius client and server.
not so the client must surf to an website and login the client AP should do the login. this is just for security.


it look like we are going to use DD-WRT or OpenWRT