for the 4 door car, how about making rear row seats face backward to get more of the vertical heavier part of the human body's vertical weight when sitting (imagine a blueprint from the side of the car) sitting in the middle for a more mid engine feeling steering feel when2nd row is occupied. the Konigsegg Regera also has this really nice arrow looking(looking from above, birds eye view) seating position that gives a narrower front end which can help with aerodynamics and it gives front row drivers a more center of the car visual perspective, which especially cool for the driver. smaller cabin space also means teh A/C or heater heats and cools faster b/c there less cabin air space to heat/cool, so a smaller A/C heater system can be used to save weight and energy needed to heat teh passenger and their cabin space. Smaller cabin space also means less mass needed to house the space, cutting car weight and maybe helping aerodynamics. also, if the trunk space is not fully being used, it can be open for more leg space to stretch out on long drives or just lay back, while the car size and mass is less compared to teh same amount of leg space in a more normal setup where back seats are forward facing and legs cant stretch into the often not fully used trunk space. This would also allow for a more 2 seater car look despite being 4 seater. and maybe its safer for rear seating people too in event of foward end crash? (search Why Kids Should Stay Longer in Rear-Facing Car Seats consumerreports.org) and for a back end crash the the front row occupants would have the same advantage.
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