Some of the fundamental trade offs comes down to $$$$$$ and application need IMO besides the obvious.
Does it make economic sense to do a SAS? IMO not really unless you're the small percentage on the board who routinely wheel stuff challenging enough to really need it and/or you're breaking the IFS stuff. But then again we all like fast cars so we can hit the go pedal on the off chance there's the slightest bit of daylight on the freeway.
Seriously the weight/aerodynamic changes are a factor from the gas pump to the extra demands on the cooling system, etc. One thing to remember is that with a SAS one thing leads to another and resale is normally not good to heavily modified vehicles.
With that said you have to be devoted to do a SAS on a Nissan, I guess I'm nuts since I'm working on my 2nd
Brian