You've got to think out of the box, bro. The possibilities if this comes to fruition are immense. Distance will no longer become a hindrance. MNCs and Companies will not be hindered and can locate their set up more efficiently. For example, you can locate warehousing, production or service centers in KL while maintaining engineering and rnd in Spore so as to be more cost effective. Having a meeting in KL and going back to office in Spore within same day becomes a possibility. How about staying in KV and working in Spore? Those are just a couple of examples.
I'm sure the more imaginative ones will come out with more.
In any case, you mentioned about city transportation, what about the MRT rollout?

its possible becoz have huge land buffer there for integrated station of KLIA express + HSR