Electronics/fueling between the GS and GSA are identical. It's all in your head.
People who say the GSA is more roomy? It's in your head. The chassis/frame/rear subframe is identical.
Seat comfort and options on both bikes are identical.
The wider tank of the GSA is less comfortable over distance compared to the GS. Unless you like keeping your legs splayed apart... it is not a natural position for most over a long period of time. Unless you're a cheap hooker...(!)