Use alot of penetrating oil on the turbo studs and also on the exhaust elbow bolts, assuming you'll be transferring it over to the new turbo. Should be a 15mm IIRC if its still original hardware.
Also have a gasket scraper on hand to remove the old turbo drain gasket. A razor blade will work too. Mine was a colossal PITA to get apart when I took my stock turbo off. I used some black RTV to hold the gasket in place to the drain tube during reassembly. Could also use studs instead of the stock bolts, as I hear this makes lining it up much easier. If you use the bolts, get the both started before you tighten the turbo down.
I have a copper gasket on my turbo flange, but you may not need one. Just make sure the flange is flat. I think I smeared some Ultra Copper on there once before and it worked well. And I agree, replace the feed line while you're in there.