hey mate welcome to the forums, you prolly gonna get flamed for "not searching" but i know what you mean, hard to find good answers, so ill help try ya out a little
-4agze bolts up to stock ae86 gearbox (T50)
-also bolts up to stock engine mounts, so no custom anything to hold it in, use 4ac engine mounts
-fuel system will need to be something decent, id go with a surge tank setup, bit of info around about that, using a lift pump and a VL turbo fuel pump. you'll to get a bigger feed fuel line, and use stock one as your return.
-good idea to upgrade the radiator, good upgrade is st162 celica radiator, twin core/twin thermo fans
-i belive it is engineerable, so long as you got brake upgrade to suit, but i havent done or tried to get it engineered
-you'll need a new exhaust as well (with most engine conversions)
theres some important stuff im forgetting i know it, but that gives you an idea
pretty easy conversion, hardly different to 4age from what i gather
hope it kinda helped
-David