Which Ubiquiti units have 64 megs of RAM

I have a Bullet M2 with tunnel and meshchat installed.  It doesn't always boot completely and is very slow.   
I've removed the tunnel package and it is much peppier but now I've lost the tunnel.  So, I guess I'll have to buy a 64 mB unit but I don't know what to get so I'm looking for input.

I have a parabolic antenna with an N-connector on it and hope not to have to buy another antenna.

Since I upgraded my node and the sister node across town to the latest firmware, even with an LQ and NLQ of >90, it's like being on dial-up.  It takes 30-40 seconds for a Mesh Status page to refresh.  I'm considering moving both nodes back one version, but that's another topic.

Thanks in advance for your help.

Rob, W8MRL