I remember a couple of things of the SPX... one is SKYDROL.... beurk.. Second the engines -40 like the Falcon50EX. Third is the APU extra bleed air switch, and the APU start in general ... a chore.... The extra range tank ( removable).. and duck-walk tendency on full reverse ( i know full reverse blablabla..lol)
I liked the deice boots, did not like the narrow cabin but very quiet due to the engines seating something like 8 feet behind the aft bulkhead.
I would not buy one, but it was a good plane..