It varied year-on-year. In 2002:
S didn't have ACE
GS 5-seat did have ACE (but was cool-sprung)
GS 7-seat didn't have ACE (but was air sprung)
higher-spec models did have ACE
IMHO - OK (and a real advantage) for air sprung vehicles, waste of time on coil-sprung vehicles...
If you are buying, look for corrosion on the pipes behind the front drivers-side wheel. You will see 4 pipes to the rear of the wheel, they go into an actuator box - that is usually where the expensive repairs come in...
You can easily remove ACE, but you need to swap the front anti-roll bar, as well as take off the pump (driven by auxiliary drive belt), and tell the "brain" there's no longer ACE in place.
If you have coil springs, take it off as/when it causes trouble...
If you don't like gadgets, buy an "S" - no ACE, coil springs, and no sunroof to leak!
Mines a GS 5 seat, now without ACE, (never had air suspension - always coil sprung) but I still have the leaky sunfoofs. I bought the GS because I like climate control which didn't come in a "S" model.