I would not buy a larger Mustang.
My 2017 Mustang is already wider than an FG Falcon and just as long.
It also has a huge 12.1 metre turning circle, which is more than a Ford Ranger or a Falcon.... You really notice it on normal side streets and most roads, and often its a 3 point turn or risk getting gutter rash on the front wheels.
So, no, the current S550 6th Gen Stang is already too big and heavy IMO.
A lighter Stang the size of a Toyota 86 / Subaru BRZ would be Heaven!