You'll need the engine and the loom out of the Gt and a good mechanic
the engine mount's are the same so it shouldnt be too hard to do if you try the search post's you will find one that's been done already I think it's in Holland....
the bakes should man and like said in the link above you will have to make one loom out of the 2 you will use all the engine loom out of the gt and then some of the dash loom and join it to the dash loom of the corolla