To be used as a winter training bike on the road and to venture off road including racing, I am considering replacing my winter road bike with this more flexible option.

I have seen this which has 105 components and I would not really want to drop below a 105 spec but has anyone got any suggestions for alternatives that won't let me down on a tough race? Perhaps lugs for mudgaurds would be useful edition if I am to be riding in a winter group.

http://www.wiggle.co.uk/p/Cycle/7/BM...ke/5360040232/

Also what are the best off road tyres to use and what is the minimum width for road tyres - would I get a 23mm clincher on?

Thanks