Not into aluminum. That’s fine.
50 lbs. not a big deal? I agree. Dependent on the goal of the car, it may be desirable.
Good X heads flow that, not all of them. Regardless, X heads don’t port out to plus 300 like these can do.
The bonus of staying with OE style gear is no extra expense! To equal the Magnum gear, the gear is more expensive for the LA though.