This. Ballast is static weight in the car. Having 10-20kg of static weight is fine, 120kg of static weight creates an inertia problem within LFS aka bad handling. The weight added currently is to the middle/rear of the car by the new engine, which might create problems but testing will only tell. Also, the car would only need 70kg of ballast, not 120.
Look where I live on the map, and look where Deko lives on the map. Two different places.
I mirror oscar's sentiment IC8 would add something new and interesting to the table tbh. I say do it.
Or at the very least test it out. Open up the tweak and test it out. Then do a test race. If I can keep it on track then there's no reason why anybody else cant