I think I would end up with 390-400bhp aswell.
James has the willy waving numbers at 400bhp, but that's 400bhp below 5500rpm, post 5500rpm the power tails dude to turbo VE, the loba will continue to make 400bhp by 7000rpm and will be 50bhp+ up on the Ko4.
It's two totally different tuning methods for each turbo, small ko3 ko4 turbos need to but worked hard midrange to get the area under the curve, fast strong spooling.
Where the bigger turbos/hybrids get tuned for extended area under the curve, trying to hold the torque flat and ad long as you can, this will make the rpm carry on climbing up to the rpm limiter. The faster car would be the one with the most area under the torque curve.
I have my first ko4 hybrid to tune in a few weeks.