Your almost there mate. Get some sard 850cc injecotrs and a bosch 044 from slide. I would have thought the z32 would be up to the task, if not i am sure someone here with will no what to get and where to get it.
Unfortunately the mechanic has underestimated the project. Pretty common though.
Good luck and i am sure you will get your desired power figure soon. I am sure the tuner will probably do the extra tuning for free too