OEM = Original Equipment Manufacturer (stock replacement parts)
MAS = Mass Airflow Sensor
MAF = Mass Air Flow sensor. ;^)
FSM = Factory Service Manual (available from Dyment)
ECU = Engine Control Unit
LSD = Limited Slip Differential
VLSD = Specific type of LSD (you know, like blotter, rainbows, x-men...)
SOHC = Single OverHead Cam (1989, 1990 models)
DOHC = Dual OverHead Cam (1991-1998 models)
S13 = 1989-1994 240SX
S14 = 1995-1998 240SX