PSM =
Porsche
Stability
Management
PASM =
Porsche
Active
Suspension
Management
They are different things. PSM was once optional on the 986 but became standard on the 987. Those who track say it hinders fun by interrupting the car vs driver desires. When first out, some at the track called it
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Me
PASM is a suspension system. Either your car could be "base", "X73 sports package" or PASM equipped. X73 was stiffer and lower springs/shocks. Was maybe $800. PASM was more complicated and priced accordingly. Eventually, even the X73 was phased out and I believe had a very low take up rate.
That said, Panorama did a compare of a PASM vs X73 cars and iirc, they actually suggested the X73 is the better system.
All that said, if you are going to rip out the suspension to build a race car, than non of it really matters.