Sounds like you're from the States/Canada but that's just a guess...(Plymouth is a very North American-ish brand....)
There's no Plymouth brand here but the Voyager is marketed under the Chrysler brand. I think it's essentially the same vehicle with some cosmetic differences.
If it's a 7 seater you're after, there are many other options, some of which you might not have seen in the country you are coming from. There are some JDM (Japan Domestic Models) that are imported grey into this market which can be quite attractive. There are the Korean options as well...which if you buy pre-owned, do not depreciate as rapidly as the other brands.
I think at this point in time when pre-owned car prices in Singapore are at an all time low, it's worth doing the sums to see if buying pre-owned is viable for you. The most important considerations in a transient resident's case would be the time horizon you're looking at, your specific needs, overall costs, cash flow and depreciation. Once you've put these pieces together, you can work out which option is better for you...
If you need more help, please post a reply to this message, maybe leaving your email address and I'll get back to you as soon as I can.