i was a tire mod on an acura site and what i found while doing that, is that you dont put anything bigger than 19" rims on a small car. also tire stores dont know **** about proper size fitment and only care about the sale.
on width, well once again its a small car and once you start pushing past 9" width it gets iffy on rubbing. also the BIGGEST factor everyone screws up is the offset. this can be center, positive or negative depending on the cars suspension setup from the maker. acura's used a positive offset and a pretty high one at that. the offset is based on the lug mounting area in comparison to the edge of the rim.
so basically you need to find out what the offset of the stock rims are and then compare that to the rim you want to put on.
also i fully agree that 11" width rims are a serious stretch fitmentwise.