Do the turboback and the UP at the same time. You need to have the DP off to get to one of the UP nuts anyways. And get manifold->head gaskets too. If you take the UP out the bottom you need to take your manifolds off.

I would recommend taking all the heat shields off the night before and soaking all the nuts/bolts down with PB to let it sit overnight, if you have an older car.

Too bad that taking the turbo out can be a pain... oil lines, coolant lines that will likely leak all over you while you're working, reinstalling it into the inlet pipe and getting the oil return line back on. Plus you'll need those little copper rings for all the lines.