an m50 swap would be under 2k. m3 cams, injectors, some bolt ons, and be in the low 200s at the crank
i dont know about the damage though, could be bad.
i also wouldn’t turbo an automatic, shit can’t handle it
i have a spare getrag 260 for sale, I don’t know what tranny the m30 uses
i would just mod the m30, it’s a good motor