Overseas headunit from US & Europe shortfall would be the following if you don't mind,
- no warranty but then if you get a new headunit who cares right
- europe headunit comes with a shorter radio freq from 87.5 - 108 Mhz & still can receive many of our local radio stations
- US headunit radio channels doesn't have even number stations after the decimal eg. You can't get 88.80, 102.20, 96.8.4, so you still can get channels such as 94.5, 99.90, 105.7

No booster is required like those jdm radio. I myself has played many brands, clarion, pioneer, alpine etc. due to their attractive prices!