Not too hard. Best bet is to pull the old one and send it off to a shop to have it rebuilt. They will probably put in a new cartridge (center part). Look up Majestic turbo or Dallas turbo (sorta the same company) on the net. They have done work for me in the past and I was happy with them. They have a lot of good info on their site. Be sure to get new gaskets including oil supply and replace to oil drain line o-rings and grommets.
Remove the battery tray, the air cleaner and anything else in your way. Use socket on universal joint with extension to get some of the turbo to exhaust manifold bolts off. Take the oil supply line off completely and run a bunch of the strongest cleaner you can find thru it. Don't want anything bad getting into your new bearings. (You can buy a new line for about $100 if you prefer). Put the exhaust parts back together with anti-seize paste. Some poor devil will have to take it apart again someday..might even be you.