Buying parts from China?

Hi guys,

I need to get two DSC pressure sensors for my 2005 e46 318ci

this is the BMW part number:
34521164458

I've been quoted everywhere from €120 - €160 each for these things.

They're so small and non-complex looking, I wonder why they're so expensive ?

anyway, can get them for around a quarter of the price from china, see here:
http://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20150413043300&SearchText=34521164458

I own an IT repair company and we often buy in parts in bulk from china from that website, but i've never bought car parts from there before. The electronic stuff is ok because it's all made there anyway and a lot of the time i'll get the exact same stuff that i'd get in ireland

my questions:

should I buy from china?

is it actually a complex part ?

is there much to go wrong ?