Long time BMW guy here and I have not missed them one bit.
If you prefer the M type suspensions, go find a secondary market (non-CPO) P85+. You will not have second generation seats but it is otherwise a very good value. The CPO program tends to cap used values which should make a private sale purchase more attractive. I'm not sure the CPO will add much if anything for you, especially if you will be a short term (a year or two) owner.
^ This. The + is much closer to BMW suspension than non-plus.
@OP: I ended up taking the short term view of "dipping my toe in the water", and in the end buying a 60 for cash I felt I could "gamble" (bear in mind I'm in the UK and I still had concerns at the time it might not be a desirable car come resale given our infrastructure and Tesla's immaturity in the market).
TBH I'm really happy with every aspect (even the 0-60 and hp figures

) But the one thing I miss having had the P85+ loaners is the + suspension. (Unfortunately the P85+s always seem to come with the darn uncomfortable gen 1.0 performance seats. My non performance gen 1.5 seats are MUCH more comfortable

)
So buying a CPO'd P85+ as your equivalent to my "dipping your toe in" would certainly be a prudent move!