wheel/tyre combo on bog roads

thanks for all welcome messages;
a mate dawked one of my alloys fairly well, might be an excuse to look for a new set...
a question, though:
02 wrx has standard 215/45r17 on at the moment, but given the rotten roads around home, would anyone think a 205/55r16 would be a better idea, I'm sure many of you have moved between both and would be good to hear your thoughts..
my driving is 95% to and from work, the remainder the odd roast in the country, but am fairly easy on her really
thanks!

I have 225/45/18 Bridgestone Potenza re030's On my forester and they seem to cope very well with potholes and the likes, SO they must have a very good side wall!
I think just avoid rain tyres as they tend to have softer side walls,
You can also get higher load rated tyres! they'd be alot stronger! I had then on my last forester sti and they were 225/45/17's
I would go for 16"s
Dan