stock twin removal isnt too bad. ive done it twice now without any major problems, it just takes awhile to do. i did it without the manual both times. i would just remove the turbo's still attached to the manifold, it seems a lot easier this way. i just used an open end wrench and a lot of pushing to get the underside bolts on the exhaust manifold, theres not enough room to really get some kinda of "cheater" bar around the wrench to get extra leverage.
The single turbos use the same ports for the oil feed and oil return but it should come with differnt fittings to attach to the new turbo. you will have to put a bolt in the other oil feed to block it off because theres 2 feeds for the stock turbos.
after you get the stock turbos out its a snap to put the new single in if you have all the neccessary parts.