I remember the ground designs (i think they are the inventors of the black widow body kit(s) company modded a crx that is now all over car shows nation wide and was a highlight of an issue of the HCI magazine. I think they are in cali and i specifically remember them stating = its a street legal setup = either a b16 or b18 with a vortech supercharger on nos.
so yes i do belive you can mod your rex like that and have it street leagal in cali.