"Can you turn a 2.7l into an S competitor for a reasonable price? If so, do you lose drivability and reliability?"
You can pick up 25-30 hp in a 2.7L boxster making it similar in hp to an "S", but in my experience, it is cheaper to buy the car with the 3.2L engine in the first place. My modded 2.7L is wonderfully drivable and with over 70K miles on the car, 30K with mods, it has been very reliable.
Ed
