ok so looks like with the single avcs heads, those are biggest cams you can get without head modifications. I have the same cams and turbo but with the non-avcs heads.
They are a good choice for the turbo, because the turbo is a bit on the big side for the motor. I am making 330kw with E30 and 27 psi boost... I seriously doubt it would
make 400 kw with these cams... they are aimed at throttle response and not high rpm. What size turbine housing do you have?
And it's not bigger ports you need for the higher lift cams... you just need some metal removing to allow for the larger lobes to rotate without hitting things. I would
get it done if you really want 400kw. It's not a lot of work in the grand scheme of things and you could do it yourself with just a dremel.
You should think about drivability before deciding on what cams... is it a track only car or something else?