What I saw in another thread was that there are a couple of Stage 1 tunes that keep it within spec, one giving about 56 hp and the other taking you all the way up to 530hp. The general consensus seems to be caution/hesitation at this stage since it's a brand new powertrain and combined with the hybrid functionality, it could hinder or even boost the charging performance/fuel economy.
I'll be waiting another couple of years at least to see what the longer-term/broader results are once more than a couple of people have done it, but if it's safe/stable/etc., I'm all in on that.
(Tuned my F-150 ecobeast and it was night and day difference)