engine: everything fits, you will also need the power steering rack and line from the v7, as for topmount make sure u get the remote clutch thingy that sits on the firewall that got the clutch pedal too unless you doing front mounts
gearbox: fit, make sure u got the hubs and diff problem will accure is the brembo hopefully u got a 4/2 pots brakes already? and wheels that will fit over brembo brakes
wiring/loom: fit if u got a full loom and dashboard u can do a swap conversion just have strip everything down and get the what u call it i cant remember bar that go under the dashboard modify, this way you can use all the wiring that comes with it. this is how i done mine. the other way is to merge the ecu to your existing dash wiring which isnt so hard to do but can take some time. heres how you can do it: http://www.rs25.com/forums/f128/t141937-brydon-teaches-you-merge-harness.html or you can pay someone to do it... you dont need to buy an expensive link unless you are rich enough to do so... but if you are planning to do the merge make sure u keep the OBDII plug for reflashing/tuning
this is my car here but with V8STI mods
http://www.rs25.com/forums/f145/t148183-spanku-v4-sti-ej207.html
Sean's Gravel express: