My "don't miss" includes:
Mickey's Philharmagic
Haunted Mansion
Splash Mountain
SOARIN' (I loved that ride!)
RNRC
TOT
Wishes
Fantasmic
Illuminations (my favorite)
It's all good! But I think Lights, Motors, Action was overrated. I learned a couple of things I didn't know, but other wise we did it once and although we are glad we did, it won't be on our list to repeat.
If you are running out of time and haven't caught it yet, but there are other things you want to do, do them, IMHO. There were 14 of us in our group when we saw it, 3 of the guys were race fans...really in to cars...and they said it was kind of a disappointment.