Personally haven't bought from this seller but have bought spacers like this from similar suppliers. If buying again I would go for a brand name such as H&r or tPi. Reason being they will be much lighter and from experience better feel from the steering wheel .
Decent feedback and plenty of sales................That's pretty reassuring.
I bought from
http://www.ebay.co.uk/itm/BMW-Z4-E85-BIMECC-HUBCENTRIC-SPACER-KITS-15-AND-20MM-INC-BOLTS-AND-LOCK-SET-/300740229297?pt=LH_DefaultDomain_3&hash=item460583b8b1
but i am sure your sellers products will be fine