Cisco Firewall :: NAT-Control Feature In ASA 8.4 (2)?

I'm a bit confused about new NAT functionality in Ver 8.4(2). I've gone through all the documentation as well as different blogs but still not clear about the various things.One of these is NAT-CONTROL. I understand that this has now been removed. Does this means that traffic traversing the ASA doesn't need any NAT'ing commands unless specifically required by the administrator? In other words by default traffic is allowed through the firewall without any NAT'ing.
 
My Second Query
 
I've ASA5520 running ver 8.4(2). For inside interface, I've created 13 x sub-interfaces under Gi0/1. All have same security level i.e. 100. What I want to achieve is that:Traffic from these sub-interfaces should be NATTed to outside interface when going to internetBut, intra sub-interface traffic should be allowed without NAT'ing. I'm using RFC1918 on both sides i.e. source / destination The first point is not a problem it's working, however. I'm struggling with the second point. On ver 8.2, it wasn't a problem, I used NAT 0 with access-list permitting RFC1918 addresses as source and destination.