I dont think you will have to get the engine engineered, just upgrade to 34 GT-T rotors and calipers and you should be fine with regency. FMIC's do not need to be engineered, however they will only be legal if there is no cutting/modification to the reo, no cutting/modification to the chassis and it is bolted on correctly so that it deosn't move around (including the piping). AFAIK anyway...
Definately a sweet little project you've got yourself, good luck!!