I'm not sure that the upgrades to SLX level parts are really going to be noticeable on a touring bike loaded down with gear and a rider. Some folks say that deore parts are rugged because they are a bit heavier and use more steel in their construction. Two friends of mine crossed Canada on two LHTs and one built this up custom with choice parts and the other rode a stock bike... they both made it and neither suffered any appreciable mechanical issues so my opinion is that upgrading to SLX isn't really worth 400$ extra. I've built up plenty of bikes and it is a fun experience but if finances are the primary driver behind this purchase either buying a used custom build will give you the biggest bang for the buck. A 2x9 setup is fine for touring, a 42/28 give a lot of lower gears and 42x11 is more than high enough for touring. You're also likely to find lights/racks on used bikes and I didn't see any of those on the wishlist either.