Attention: TDR Forum Junkies The oil drain gasket is made of a heavy gasket material, and installed right should not be giving any oil leakage problems.
Where the problem comes in is in clocking the turbo.
You should mount the exhaust housing onto the manifold & tighten it in place. Then loosen the 6 bolts that hold the cartridge to the exhaust housing, rotate the cartridge until your oil drain tube lines up dead level with the oil outlet flange on the cartridge.
Now put in your gasket and tighten up the two bolts.
Now tighten up the six bolts you lightly loosened, making sure the pinwheel is turning free whilst tightening [ tighten the top bolt first] Now if your drain tube won't clear the compressor housing or the turbo outlet fitting doesn't line up with the elbow going to the intercooler, then snap a pair of vise grips onto the snap ring that holds the compressor cover onto the backing plate, adjust your vise grips so when compressed they are able to hold off enough tension on the snap ring so you can rotate the housing into perfect alignment, DO NOT take snap ring out, it is a major pita to get back in again. Once that is complete then prime your new turbo with a couple of cap fulls of clean oil, then attach the oil fill line. When you start up any new turbo let it idle for 5 mins. Check for oil leaks, etc. Then take it easy for the first 50 miles [less than 10-15 lbs boost] After that go ahead and use full throttle, just try and ease into and out of the throttle for the next 100 or so miles.
Where the problem comes in is in clocking the turbo.
You should mount the exhaust housing onto the manifold & tighten it in place. Then loosen the 6 bolts that hold the cartridge to the exhaust housing, rotate the cartridge until your oil drain tube lines up dead level with the oil outlet flange on the cartridge.
Now put in your gasket and tighten up the two bolts.
Now tighten up the six bolts you lightly loosened, making sure the pinwheel is turning free whilst tightening [ tighten the top bolt first] Now if your drain tube won't clear the compressor housing or the turbo outlet fitting doesn't line up with the elbow going to the intercooler, then snap a pair of vise grips onto the snap ring that holds the compressor cover onto the backing plate, adjust your vise grips so when compressed they are able to hold off enough tension on the snap ring so you can rotate the housing into perfect alignment, DO NOT take snap ring out, it is a major pita to get back in again. Once that is complete then prime your new turbo with a couple of cap fulls of clean oil, then attach the oil fill line. When you start up any new turbo let it idle for 5 mins. Check for oil leaks, etc. Then take it easy for the first 50 miles [less than 10-15 lbs boost] After that go ahead and use full throttle, just try and ease into and out of the throttle for the next 100 or so miles.
. That's what I get for doing the install over a long weekend! 
