The exhaust gives 6hp and 14lbs of tq. at the wheels. Which is great thats a almost 10% increase. a must it will offset the a/c on.I have raced since I have been 9 and My brother has a race shop in town so getting stuff out of cars is what we do.
If you are looking for true 150hp It would be cheaper to install a Hyabussa. To get that hp first is a re-map/ changing the injectors / turbo w/innercooler /exhaust / and you could get 115-125hp at wheels.That MR2 motor sounds good. We use to race for Toyota World Sports Cars and used the MR2 motor.
But don't forget Emissions for the car.
If you are looking for a small car (A.K.A a sleeper) MiniMania.com makes an old mini cooper and put in a 1800 VTec honda motor.You can get a 1960's title and no smog.
If looking to just turn heads and do burnouts. A bleach spray system for the rear tires might work. Have to check to see if that anti-roll back plays to much into the take-off.
But would be funny to watch
nitrous NOS in a Smart Car - 451 smart fortwo go here this is in the back of my wife's smartcar. click on the attatchments pic.