Well he said it was classed on what car it came out of, but I agree with you, it does kinda make sense that a modified car is a modified car.
It would be easier, but not neccessarily cheaper. If I bought a valver, it's gonna cost me at least £1000 for the car, gonna have to cancel my insurance, take out a new policy which could as far as I know, be more expensive than my current one plus the modified excess.
I could probably get the engine, loom, and everything I need for about £500