Great idea, great modification to the game! Really makes it scream "BMW" a lot more than the vanilla ETK I-Series. Like you pointed out, j-beam and deformation isn't that good, which is why I gave a 4 star rating. Once this is fixed, I'll update my rating!
Sure its a good idea, and a good looking one as well, but i think you either change more of the car, or turn it into pieces for the I-Series. Because as of right now i see no reason why it has to be an entirely different car.
Other than that, keep the good work.