Modern Warfare 3 Xbox 360

I have looked on eBay and the cheapest price for MW3 on Xbox 360 is the ones that are shipped from Hong Kong, the game states it’s US version, so what’s the difference?
http://www.ebay.co.uk/itm/CALL-DUTY-MODERN-WARFARE-3-BRAND-NEW-SEALED-GENUINE-XBOX-360-GAME-COD-MW3-/220880631014?pt=AU_PC_Video_Games_Games&hash=item336d82f4e6
Answer #1
NTSC/U =/= NTSC/J = PAL
Answer #2
prozac4312 replied: NTSC/U =/= NTSC/J = PAL
I live in UK, so my console is PAL so it will work on it but what’s the difference between the UK and US MW3 version?
Answer #3
MW3 is about £35 in Morrisons / Sainsburys.