AlmostThere Max there are good and bad issues with both supercharging and turbos. In the last 2 years the turbo lag has become a thing of the past. If you get the correct housings and turbo pinwheels, you can have almost no lag at all. I agree with compression of the motor in the 9.0-9.2 area. Street gas in the 6-8 pounds of boost. Race gas with the correct FI system. 15 limit. Make sure you have a min of two bypass valves, 4 small ones are better with 2 opening at 6 psi and the others opening at 8 psi. This also pervents turbo surging and damaging impellor. Snow makes a good water injection system that works like a fogger. They are adjustable. IMO works as good as an intercooler and uses less room. Just have to remember to fill the tank. They only turn on when you are running boost.
Superchargers IMO are easier on the motor with how boost is built. The only issue I had with my setup was running clog belts and banging the supercharger. The belt would belly and pop off, Vee belts work better and also limit the amount of boost you want to run. They slip around 10-12 psi and do the same after a WOT and you go to idle quick because the blower can't whine down that fast. Are you going carb or FI system for your car? Either way, 1/2" fuel line to the motor and return of 5/16" back. For every pound of boost you want a 2 psi of pressure added to a carb setup. I ran a 3-1 ratio with my FI system. My injectors where oversized for my setup.
Heat like Fred said is another issue under that hood, You need cool air coming in and removal of all the hot air or heat shields, coatings of the metal and small fans to help remove the hot air. A large radiator is also needed with a good 2,500 min cfm fan and fan shroud to move the air. Over build the drive train too.
Build what every you want, but understand that a cobra with this kind of power, short wheel base, primitive controls will be a hand full. 400 rwhp is a hand full you are looking in the 500-650rwhp. This car don't have traction control, ABS, PS( some now do like mine) and "G" meters. You might want to build a motor, NA and then go for broke with another motor.
Are you looking for a ford or a GM motor? This will also help in your info hunting. Rick L.