The 105 crank is wonderful on the 520 if you never carry anything. However, put some loaded pannieries on the bike or tow a trailer and that 52 ring becomes dead weight. Switching to a mountain bike crank such as LX or XT will save your knees. There's really no need to have a 52X11 gear combination on a touring bike. If you look at the custom builders, they all use mountain bike cranks. As for a saddle, it's hard to tell you what to get. For me it was a trial and error process. I am finally happy with a WTB speed V. (bought 3 of em and put in the parts box for the future.) Some people swear by Brooks B17 but I have found I can't get comefortable on one. I'm either leaning too far forward or mashing my privates. Most bike shops will let you try out different saddles over the course of a few days. That may be the best way to find one you are happy with.