I'm assuming that English is your native language, and that you're
talking about using the gear in North America.  If this is the case,
there are a couple things to keep in mind.

For DVD players, make sure that the player works with "Region 1"
discs.  Also, the video standard for North America is NTSC.  Some
countries use PAL or SECAM, and unless the player can handle multiple
formats, they're generally incompatible.

Be aware that the language used for the unit's firmware may not be
English, so all of your on-screen displays might be in Chinese, Kanji,
or some other language.  There's an entire cottage industry devoted to
taking car high-end consumer electronics products that are available
overseas but not in America, and converting the firmware, keyboard
logos, etcetera to English.

Also, the frequency ranges and channel spacing for FM and AM radio
vary around the world.  For instance, in the US, "FM radio" covers the
range from about 88 MHz to 108 MHz, with a 200 kHz channel separation.
That's why we have stations at 97.1 MHz and 97.3 MHz, but not at 97.2
MHz.

In Japan, "FM Radio" is from 76-90 MHz, so for a tuner designed solely
for that market, it wouldn't be possible to tune 97.1 Mhz at all, and
you'd be picking up the audio broadcasts for local TV stations in the
76-88 Mhz range.

In Europe, the channel spacing is 100 kHz instead of 200 kHz.  That
means that if your radio has 100 Khz spacing, and you're using the
seek/scan function, it may stop at 97.0 Mhz, even though the station
is actually broadcasting at 97.1 Mhz.  The signal at 97.0 MHz will be
distorted, but it will still be strong enough to trigger the seek/scan
circuitry, so you'd have to manually bump the frequency up to 97.1 Mhz
to get a clean signal.

Before you go, get a feel for what units are available here in the US,
and how much they cost.  Honestly, I'd only buy something in Singapore
if it either wasn't available here at all, or if you could get it for
MUCH less money over there, AND you're certain it will work when you
get it back  home.