I believe the 1991-1995 550SX's have 47 H.P. The SX's are the only ones I'm not 100% about. I'd say 47 is just about right though as my friend had one and it was not quite as fast or powerful as my...
140 H.P.
Think its between 300-350
about 200-210 vin W 150-185 vin Z
It's a measure of how strong the engine is.