I'm lucky in that the EMM chip (or whatever its called) hasnt caused my MCU1 to fail yet, although its sluggish.
Have a look at the MCU2 upgrade, its well worth the money, makes everything quicker.
I think a Y would be good, but I suspect it'll be a close to £35k+ for cost of change from your current car, and regardless of what hardware advances there is I still think the S is the best looking car Tesla makes.