Just remember to carry your mod in your carry-on baggage as it is not allowed on checked-in baggage.
You can dismantle your tank and hide your eliquid as much as you want. It doesnt really matter cos if the officers at customs want to check your baggage, they will most probably find your PV no matter how much preparation you do.
As someone earlier said that Singapore has nothing to gain from antagonizing tourists, maybe if you get caught just feign ignorance and perhaps the officers will just confiscate your PV without fining you. No promises tho.
Also, I don't know if you'll be able to bring your PV out of Singapore when you decide to leave. All baggage have to be scanned when you depart so they'll and I'm not sure you'll get charged for possession since you ARE already leaving the country. Can anyone advise on this? In any case, I would suggest buying a cheap PV and dispose it in Singapore when you're leaving.
PS if you decide to bring your PV, could you bring some supplies from the USA for me?

jk