I recently did a compression test on a Nissan B13 GA16DE and got 125, 127, 122 and 140 PSI (cold). A few years ago, all 4 cylinders got 135-140 PSI, cold. Shouldn't this loss of compression have led to a commensurate loss of power?
Yes, it does lead to a loss of a power, but your compression is not worth worrying about. Every engine will loose some compression after a few years. New rings wear out faster at the beginning and later they wears out slowly, so probably you won't see a difference for another 2 years.
Those numbers do not seem horrible, unless the 140psi is low. You might want to repeat the test with the engine warm. I generally feel that a cold test only reveals inter-cylinder differnces (in your worst case only 18psi), but dynamic compression after everything is warmed up and expanded might be much better.