Sadly not true, I'm afraid. Here's a Powertec V8 in the back of an OMS hillclimb car. That car won the British Hillclimb Championship in 2012.
The car generates significant downforce and I'm not aware of it splitting in two yet.
Even when he crashed it at Prescott in April, it shattered a wheel and the rear wing without damaging the engine.
I'm pretty sure the Hartley engine being used in this project is also up to the task. The reason the SR8 has a rear subframe is simply because it was built as a bike engined car and the V8 was dropped in the back. The SR8 is essentially the same car as the SR3, which comes with a variety of Hayabusa engines.