If it's S50 then you need to look at fiat 33mm shims
Or this link http://www.eurosport-uk.net/shop/ind...products_id=45
Or of course BMW
If it's S50 then you need to look at fiat 33mm shims
Or this link http://www.eurosport-uk.net/shop/ind...products_id=45
Or of course BMW
Those fiat shims are made in Italy and are more than likely the same shims Ferrari use in the their engines that require 33mm shims.
I will be buying from that website when I do my s50 valve's