Subang is now known as Sultan Abdul Aziz Shah Airport or SZB.. I don't think Firefly being flights in or out of there till end of October.

Thanks guys! Ok then I'll purchase the ticket. I have about 6 hours to the next flight so I assume shouldn't be a problem to get to the other airport, right?

No it shouldn't be if there are no flight delays - the two airports are connected almost the whole distance by good expressways. It's about 60 - 70km.

I'll second that....
Less than one hour.... KL roads are very good. You'll have ample time.. as long as that AirAsia flight isn't completely cancelled..
I flew with them from the Gold Coast last Christmas and they were on time...
Only a couple of flights have had significant delays since they began operating the route... almost a year ago now..... that I know off.
If you are lucky you may get their new aircraft.. due for delivery soon.
Happy travels.