@stuart-88
Sorry for the late reply, I'm not getting notifications.
The hybrid itself can be had for about a grand, from Beach Buggy Turbos. Other brands are available, but they seem to be the best option at the minute, and preferred by R-Tech.
If you got all the k04 kit second hand, then arguably it could be done cheaper, but going that route throws in a few more variables. The turbo and k04 injectors might not be in the best nick, and you've also got all the pipework to swap, which is extra labour.
With a hybrid it's a straight swap, so no changing pipework, and you can even use your existing injectors. Niki mapped one to 360bhp and 377lbft recently, on k03 injectors:
You get a new turbo, there's less work fitting it, and you're not bringing used parts into the equation. Obviously you'd need all the supporting 2+ mods to hit those sort of figures, but you're not far off that, like me, especially with the clutch.
K03 hybrids were initially touted as producing k04 top end but keeping the quick spool of a k03 at low revs, but the more graphs I see the more the hybrids are pretty much doing the same thing as a k04 across the revs. They don't seem to boost as early as a normal k03, as much as it's a nice idea. I might speak to BBT nearer the time and see if they can build a turbo that's good for maybe 320-330bhp at the top end rather than 360bhp, but actually keeps the quick spool. I'm not sure if that's even possible, but I'd probably prefer that kind of power delivery.
I don't think there's a massive advantage or disadvantage to going either hybrid or k04, but to me the hybrid just seems to make a little bit more sense.