With road bikes the general advise is to try and get your winter training frame to be as close as possible to you race bike. Otherwise when you switch from one to the other the transition period may be longer.

This is something I'm thinking about as well. During the summer I made some adjustments to my summer frame, bought a compact chainset and a new stem so my winter bike is going to be considerably out of date. Can't afford to do double upgrades so I think I'll just have to go with it. The geometry is more or less the same.

I think if you able to, get as close a match as you can - but unless you're a millionaire or a pro you just have to do the best you can.