I understand that you were just using that (randomly picked) size as an example, but Federal (as well as EVERYONE ELSE, sadly enough, save for a few FULL ROAD RACE, 00-40 tread wear, SLICKS) does NOT produce ANY tire in a 16"/17" 225/40 (IF they did make a 225/40-17, they would be on my 17x8 Pro Race 1.2 summer wheels as we speak, instead of their 215/40-17 RS-RRs).
You could easily run a Feddy 215/40 17 on your ST with 17x8 inch wheels as it has a section width of 8.5 inches.
it states it right here
http://www.federaltire.com/spec/spec.php?type=gbl&model=595RS-RR