Now that the turbo's out, plug the hole where the original oil feed line went with the supplied bolt, drain the engine oil and install the stainless steel oil feed line (you need a 8mm allen wrench to remove it). Here's a pic of where the oil feed line is supposed to go on '90 DSMs according to Road Race Engineering:

Here's a pic of what the new oil feed line looks like installed:

Now it's finally time to install the PTE turbo. I found it to be easier to take the O2 sensor housing off the down pipe and install it on the turbo before putting everything back in:

Next thing to do is bolt the turbo back on to the manifold. Don't tighten the bolts down yet because you'll want to be able to move the turbo around a bit. Otherwise it'll be a major pain in the ass to line up the O2 sensor housing and downpipe. Torque the turbo/manifold bolts to the recommended spec of 40-47 ft/lbs after the O2 housing and downpipe are bolted back together. Everything else is pretty straight forward. Connect the hose and oil return line, new oil feed line to the turbo and make some new lower intercooler pipes (2 90° mandrel bends, remember to bead them so they don't blow off):

All done! Here's a pic of everything back in the car: