Y and W are speed ratings so unless your going to blast down the nurburg ring at 140mph you should be fine.
as previously mentioned, with the speed ratings, they should be more than adequate.
just for some reason on the standard monzas, there is a difference in speed ratings for the 17s and 18s.
you usually see this when you put in your reg in a tyre shop website such as halfords or kwik fit.
they say 17s should be W rated and 18s as Y rated as a minimum.
not had a chance to check the manual but ive always followed those criteria.
