Not teaching you to suck eggs at all - but if you look here there's good info on the fitment of the Laguna Silverstone wheels on posts 5,6,7 and 8: So doesn't look like you'll want / need 20mm spacers possibly....
(Just incase you didnt know - i certainly didnt having never looked into it before !)
http://www.clio197.net/threads/branxs-black-197.54455/#post-604448
(Just incase you didnt know - i certainly didnt having never looked into it before !)
http://www.clio197.net/threads/branxs-black-197.54455/#post-604448