Well anything is possible, all it takes it money. You could absolutely build it to retain functionality of all your factory instrument cluster and electronics. Flyin Miata does it all the time with the LS swapped Miatas. It's just not a plug-n-play solution. It just takes more money to make it work. So if that's something you really want, and have the cash for, then there's nothing holding you back. A V8 rear wheel drive SHO sounds awesome, and it may seem more like what you would expect from the factory in a sport sedan.
The Coyote swap would be cooler, sure. It would also be more expensive, and longer development time. LS swaps are way more common, so it would be quicker and easier to get sorted. If you do swap for an LS, then you can start with a base motor and once you get the swap done, mod the motor to your taste. The LS aftermarket is bottomless. You will never run out of things to make you go faster.
Personally, my 2 cents is this: Take the money that it would cost to swap, and put it into getting a custom, fully built transmission and PTU for your existing drive train. Once those parts can handle higher power levels, you can start extracting some real power from the EcoBoost. You could go for a legit "big turbo" set up. Have some custom exhaust manifolds, hotpipes, and downpipes made, and throw some insane sized turbos on the car. Go REALLLY crazy and be the first guy to do a monster SINGLE turbo SHO. Then smash BPD's record at the drag strip. Which will make him start chasing bigger numbers, and all the new parts that come out of it will trickle down to us peasants, lol.
So yeah, if your heart is really set on an LS, and you have the money and the patience, go for it. I just think it'd be way cooler to break through the current performance plateau the SHO platform has been sitting on.
