Know doubt. I have nothing but praise for builders who follow there passions.
Problem being, these cars are not built to today's level of power and frankly are way below the today's high performance levels. Meaning what it costs in $$$'s and man/hrs. and system upgrades compared to what's readily available falls way short; just doesn't make alot of sense to spend the kind of cash it's going to take to make what maybe 310rwhp at best?
Classic example. I have a Toyota Cressida quite similar to the one on this youtube dyno'd on cold here in Seattle @ 347 rwhp with stock turbo's. We're building a new car with a 1JZ vvti that will have more torque and should be around 360-375 rwhp. We're talking about a 2.5L inline 6! Not a 5.4L V8. Change the turbo, manifold and injectors it can make 425-450 rwhp for <$1000. Thats more than more than a 6.3 AMG motor can do.
Sorry Will, I own a MB but I drive the HELL out of that JZX.