im looking a getting a new cd/mp3 head unit or even possibly a dvd head unit,

ive seen alot on ebay from reputable ebay shops,

theres also alot of kit from the US and Japan but what are the risks with getting one from the US or Japan, as for the same price UK you can get a better spec model abroad?

are there extra hidden costs like different adapters and arials to make them work and are they all compatible,

as ive seen the same model pioneer mp3/cd player on a buy it now from a uk ebay shop for

Import duties, no FM (or is that AM?) to name a few.

No RDS , No AM , No Warranty , FM steppings are different on US models so you'll miss most of your stations , though this may be switchable.

will i not get the same fm settings etc even though you can buy the model here and in the US

will they be set up differently then?

No, the software is different to cater for the US market.