Grey injectors are flat out at 450bhp.
The t34.63 will do just over 400bhp but not for long.

When talking boost you need to know what it holds at 6500/7000rpm.

You can run the big boost in the mid range, something like 2.2 bar is what we use. And by 6500 drop to 1.8/9bar and will give a gen 400bhp. With a ported head and inlet cam.

The .48 is a better exhaust housing IMO for the road. Alot more punchy and only a 20bhp and a few hundred rpm sacrafise up the top.