Higher BHP would be more expensive so the 200 BHP one but your question is unrealistic if you want a more realistic version I had the dilemma of turbo VX and NA VX which is slower, I went for the slower one because the higher power one is turbo and not a drive style I prefer.
If you want a 'formula' you can't simply add performance numbers - otherwise why do people buy an Aygo over a used Evo? When buying cars I have a formula that looks something like:
Performance x20% + Fun x20% + Uniqueness x25% + Driveability x10% + Modability x25%
A 911 owner might have something that looks like:
Performance x50% + Drivability x35% + Allroundability x15%
Which is why it would appear ridiculous for someone to buy something which from a performance perspective is so much inferior. In addition, performance can be measured easily using stats we see everyday. Fun? Fun is a personal thing. Uniqueness can mean many different things from colour, number of seats, country of origin, availability.
I didn't say I disagree with the 911 owners, I just offered up a reason as to why people sometime veer away from going with whats 'on paper' the best.