anyone looking at nasa st4 (weight to hp of 12:1) and thinking it might be a great fit for a boxster s? about 2600 lbs (a bit less than spec boxster weight) 210 rwhp average gives you 12.4 as a starting point so room to add 5 additional hp or lose 80 lbs more weight. that doesn't include the aero adder so can run rear wing, front bumper and splitter (no rockers or rear diffusers). tires max 275 dot so a great fit for our cars - a good transition class from de or autocross.
can't get the calculator to run on my ipad, but +.3 for tire width is offset by -.1 for r-comps and -.2 for weight if you can get it under 2600 lbs w driver.