Not sure why everyone keeps throwing $200k or even $300k numbers around - won't be that much.
For one thing, the GTS costs around EUR 115k or $110K GBP - it would cost about $120k if imported in the US.
How much is a GPower supercharger? $15k?
What if they bored/stroked it even further? Another $30k?
So we're up around $/EUR 165k for a 720BHP track-ready car. Not amazing screamingly cheap, but not a bad deal either at these stratospheric capabilities.
I generally agree that the appeal of something like a GPower is for an otherwise stock-looking car. Nothing there to see, same 4 or 5 seats as the regular model, some fancy wheels and then he nails the throttle, he's gone and your brain is furiously trying to explain how your Gallardo was so comprehensively raped.
That appeal is somewhat diminished in a bright orange 2 seater GTS, but it's still a cool toy.
In the very rarefied world of people who can actually afford these cars, the GPower GTS might share a garage with a 430 Scud Spider for sunny days, a Bentley for gloomy days, a classic Ferrari for the noise & occasion, you get the idea. To these people it's just a toy, something the neighbor doesn't have and you can rape his Lambo in it...
2009 E90 M3 ED
2012 MINI Countryman S