From what I recall reading on e90post I think the 313's are also a bit of a mare to refurb as they are diamond cut or at least require a really top class professional outfit to get it done e.g. Lepsons. There was also talk of corrosion/oxidation appearing after a couple of years on them but I would hope proper care and wheel protection would minimise this.

I also considered 313's but am sticking with my 225's until I have to get something else.