Freddy intake manifold vs stock

[Loomis112]

Hey all I got a redtop with a gt2871 on it and the previous owner threw on a Isis intake manifold.

I have the stock one sitting in my garage and im not really pushing anything over 260rwhp.

So just a couple questions..

I am wondering if it would be better to have the stock intake manifold back on there?

Would it help spool the turbo by not being a gigantic whale penis manifold?

Also I have heard the stock manifolds are good up to 400hp is that total bs or is there some truth to that?

Thanks for reading