Only the sound is already enough I think !
Never driven a 400bhp Solstice but seems to me it is too much power and does not create a better drivability.
I say this with the greatest respect and kindness.
"I have no experience at this but clearly its bad"
While I appreciate that you have an opinion, your statement begins with a disqualifying statement.
I have 25k miles on a V8 Solstice and in my EXPERIENCE it does add to the drivability. And the fun factor. And the OMG experience.
You can choose to drive the V8 Solstice in a mild manner and it has great drivability. Shift early, let it lug along at the bottom of the power curve. It will return great muffled sound, smooth power delivery, and a great ride.
Give it a bit more throttle and it will perform at a higher level but it is very controllable. Having more power, be it with a highly built 2.0 or with a stock LS motor of moderate power and both will behave in a similar manner. If anything, the power delivery in the highly tuned 400 hp 2.0 is LESS controllable as the turbo power curve tends to be very steep and I have seen many tuned 2.0s disappearing over the horizon at 6000 RPM as the driver is hanging on to a charging hot rod.
For me, the decision factors were 1) longevity of the LS motor over a similarly tuned 2.0. During the period when I was faced with the decision to V8 or not, we had a LOT of built 2.0s self destructing and manual transmissions giving up the ghost. Clutch failures. Axel failures. The landscape looked like it was littered with smoking turbo motors that broke, burned up, or just gave up. 2) I tuned my 2.0 to 305 at the wheels. That is somewhere around 350 HP at the crank. In my opinion that is a power level that retains reliability while providing great performance. I enjoyed the power but I was constantly worried about every ping, every time I hit the rev limiter I looked for smoke. Every start included listening for any rattling or signs of damage. I was very concerned, probably without merit, about the fragility of the motor and transmission.
All of that went away with the conversion. Sure I had other challenges but they did not involve the basic reliability, drivability and fun factor of the V8. And many of the challenges were self inflicted as part of my learning the car.
Having a V8 is not for everybody. But it can be a great experience and a ton of fun. Its an even BIGGER driving experience. And I would have no compunction about having any competent driver drive the car. Its very forgiving and easy to drive at less than ten tenths performance.