I have both and I also added, in the last minute, PTV. PASM is useless to me because I can feel the difference only on the track, don't know about others. Roads around here are horrendous so it is always off. When I hit smooth stretch of tarmac, I am going way too slow (twice speed limit into some corners, at least 66% over in most corners) to tell the difference, frankly. However, that said, X73 was NOT an option for me (driveway, roads around me), so PASM it was.
If I were building a 981 again, and there was money for only ONE option, that would be PSE. If I were building a 981 and have money for TWO options only, that would probably be PSE and PTV.
Please keep in mind that these cars have very different intended uses by their owners. I am still, at 50, a teenage hooligan that likes to make stupid noises on the road and I bought my 981 primarily for training on empty roads and track driving, I never use it for mundane duties. Your intended use could be a LOT different and that should decide which option(s) to get. Good luck!