No ERS, they can cram it.
The structural objections you mention could be overcome with some chassis engineering I am sure. That was a legitimate complaint back in the small block Chevy/Buick V6 days for Indy cars.
Ford says the biggest change they made to the V6 twin turbo engine was the crankshaft for endurance racing. Heck, I know people that get 1,000 hp out of the Northstar engine for dune buggies. Buy a crate engine and run the crap out of it for a year, then get another engine and move the fuel injection and turbos over to it. No building crazy expensive engines. That pushrod Chevy engine in the Vette is what, 525hp and comes with a warranty?
Imagine, Vettle driving a Chebbie!!!!! Rosberg in Ford and Hamiliton in a VW.