[Bob's944]

On stock tires, this is how fast an NA will go IF it can push into the higher RPM range. There should be a similar chart in the back of the turbo manual. Reality is that wind drag limits the top end with stock HP to somewhere around 130 mph or so depending on temperature, wind, altitude, road grade, state of tune, quality of fuel and so on. Larger rear diameter tires will also make top end potential higher. You should be able to chart top speed and peak horsepower higher than stock along the curve if you know the real comparible horsepower of a modded car and it corresponding top end.