folks buy donor DSMs to get all the electronics as well. Turbo & mani fits.
LOTS of info about to guide you - water outlet, cam sensor, etc... Not a swap for the novice imo
Seen folks abroad lynch their evo3. 7 bolts no drama.
A friend bought a dirt cheap non turbo 7 bolt. Threw his gt35 + electronics on. Motor lasted, car fast
Ridiculously stiff clutch crankwalked it. Hot evo3s didn't run any of the ACT stiff crap

starion 2.6 drivetrains still available and swap far easier. Bolt-on mods make a quick truck. Wiring not hard
Either get a truck wide 5 speed or mod your bell housing... or slice the ring off one of the many dead starion boxes