Cam & head upgrade 360 mag

I didn't plan on swapping to the air-gap, I was running the edelbrock air-gap and I didn't like the way it performed in cold weather, i live in Montana where it gets real cold and the engine felt sluggish with the air gap when it was real cold out, and the fuel mileage was suffering.
When I swapped back to the mopar dual plane m1 I noticed it ran much better in cold weather and I also noticed slightly better fuel mileage.
A lot of ppl trash the m1 dual plane intake, saying its just a stock intake and they don't perform that well. I was just wondering why ppl don't really like them?
If they can support 400hp that seems like a decent manifold to me, and doesn't the m1 dual plane have larger ports and larger runners over the factory cast iron 4bbl intakes?
I thought I read that somewhere, and I like the position of the thermostat housing and the by pass hose better on this dual plane m1 over the air-gap, it just looks better and the hoses fit better in my opinion. And I like where the vaccum port is for the power brakes on this dual plane m1 over it being on the passenger side on the air-gap.