If you have a long wait for flights at KLIA2 I reccomend that you get a few hours kip at the Capsule Container.
Its like staying at a real life Japanese Capsule Hotel. But you don't have to visit JAPAN!
If you stay between 8-4 pm then you get discounted rated
I had a flight to Sydney at 11 pm that night. So i got to KLIA2 Airport at 1.30pm and I just stayed for 6 hours.
Its pretty cool and you won't regret it