To double a cars speed you have to quadruple the HP. All forms of resistance, aka friction. For example,
1/2mv^2 =Energy(kinetic)
m=mass
v=velocity
All forms of energy have the same relation, rotational mass is the same. Friction due to air, fluids,..etc. also has the square proportionality. Energy is directly proportional to power.
Let's say it takes a supra 400rwhp to run 190mph, we can guess that if we double the speed to 380mph it theoretically takes quadruple the HP, or 1600rwhp. We can say 220mph drops between 190mph and 380mph. Or 220mph is 15.8% speed increase from 190mph to 380 mph, so hp must increase 15.8% between the difference of 400rwhp and 1600rwhp. Since we said it takes 400rwhp to go 190 mph and 1600rwhp to run 380mph there is a 1200rwhp difference to run the extra 190 mph. So we figure how much hp is 15.8% from 400rwhp-1600rwhp Using 15.8%, it takes an extra 189 rwhp or 400rwhp + 189rwhp = 589rwhp for a supra to run 220mph. This is theoretical, of course this doesn't include gearing change. If you think this is farfetched, with the correct gearing a 560rwhp TT vette hit 240mph . The c5 vette has a better cd(coefficient of drag) of drag then the supra. That's to say if we didn't change any aerodynamics for downforce. Hope this helps.
Sam
PS you can also say a 900 rwhp car like Saad's can move 270 mph but most cars are like airplane wings, air above the car moves faster then air below, by that speed so it would take off w/o major downforce. With downforce comes drag so actually you would need a lot more hp. Also using my assumptions it 285 rwhp supra will only hit 160mph, therefore my calculations are on the conservative side.