Originally Posted by nov11

You don't need a visa to enter Malaysia for up to 90 days. However, you'd need to fill in the Malaysia Digital Arrival Card (MDAC) no more than 3 days prior to arrival. You can fill it in on arrival too but that'd just take up time when you are at immigration. I don't believe e-gates are installed at Penang International yet, but immigration shouldn't be that bad if you aren't arriving during the peak arrivals.

You can just use the e-gates when you leave KUL (you don't have to queue up to have an immigration officer stamp you out).