thats still just what you've interpreted from what you've heard about the new laws, so thats an opinion too isnt it - its not solid info.
he's asking a hypothetical so lets say he's got the car and the parts ready to go.
hypothetically speaking, if he got the work signed off by an engineer (engineers cert.), and told the RTA what he's done because it was cheaper than buying a non turbo car, he might be eligible for an exemption (obviously it wouldnt be cheaper, but for the sake of getting the exemption, thats what he'd say).
the fact of the matter is that the RTA is like any other government authority. there are loopholes around everything.