2JZ-GTE Artec T4 exhaust manifold

I'm changing my 2JZ-GTE VVTI exhaust manifold and I heard about the new Artec T4 exhaust manifold which is cast but at the same time it has the design of a tubular manifold which is something I didn't see much before. Anyone had experience with Artec manifolds , is it reliable and it doesn't crack , is the flow in the runners good as it is cast and the runners inner diameter is 36mm and can it handle 1200whp, this horsepower is not my target now but I want to know if I have space to upgrade in the future, my current target is around 850 whp. I'd appreciate it if anyone can advise their experience with the Artec exhaust manifolds. Thank you

Toyota 2JZ-GTE T4 Exhaust Manifold – ARTEC Performance Global

Can't comment on possible cracking, but it is cast in stainless steel (alloy?) and so should be at least as resistant as anything else in that material. If the pictures are typical, it looks like a very nicely made piece and at least equal to most fabricated tube forms.

One advantage of cast is that they can be made in a more compact form, so very useful if space is a premium, and they hold heat better.