Originally Posted by
rms13
Yup. Be honest with yourself and why you want to upgrade. Performance wise, the upgrades you are considering would be noticeable but minimal for the amount of money. Aesthetically, well the new 5800 cranks are a lot sexier looking than the Tiagra...in my opinion but some people think the new Shimano 105/Ultegra/DA cranks are ugly. But this is a hobby where people spend thousands to shave 2 lbs off a bike when they themselves are 20-30 lbs overweight so rational thinking doesn't always apply.
For me, I've built/rebuilt a few bikes now and that is as much of a hobby for me as riding is so I'm jonsing for a new project myself just because I haven't done anything in 6+ months
+1
OP: This is my main question: why the upgrade? If you want more performance, I think the consensus is that you won't get much by going with Ultegra 6700 10-speed. If it's for aesthetics, then the low cost option would be to do the shifters, crank, and rear dérailleur, since these are the most "visual" components (can't really tell the difference in chain and cassette at a glance). If it's for performance, I've read quite a few reviews that report not insignificant gains in braking and shifting performance in the latest Shimano 11-speed groups. I can personally attest to the performance of both 6800 and 5800 brakes, both of which are phenomenal (I run them with 6700 and 5700 brifters, respectively). If cost is no object, then go for the group that you like most. Either way, it's whatever gets you out on the bike most that counts.