I've run 225's no problem on the first gen 16in aluminium wheels.  I kept my diameter almost completely stock by going with a lower sidewall (don't like being caught out of lift between shifts  

 ).  I will say, however, that I will be going back to a 215 width as I believe there are a few reasons/performance benefits to be gained due to better fitment, full contact patch use, lighter overall, etc.  In other words, wider tires look nice but don't 
necessarily net you a performance increase.