Peugeot partner van..fitting ford wheels?

Hi,i've just come by a set of ford alloys that i want to fit on a x plate partner van.The size is 205/50/16,to do this wot size spacers do i need?..anything over a 175 tyre rubs on the inside..thort they might be ok on the front as i av 185s on there but the new wheels won't fit the brake callipier is in the way...HELP PLEASE