according to my info (hyperrev mag, which lists all the specs and outputs for all gen1-3+vvti 3sg(t)es) the beams has 1mm bigger inlet valves, 256/10.5in 244/9.2ex cams.
all gen3+ have staggered cam's, longer duration/higher lift on intake. which must be due to the 3s exh ports flowing well enough, ie: no gain from having long dur exh cams in overall power figures = better driveability with not having too much overlap.
the beam having larger valves is like having a larger cam, also with the VVTi allows the overlap like long duration cams in the top rpm.
along with the 65mm TB compared to gen2 55 TB and the more advanced head design and intake manifold i'm wouldn't count on getting more HP than a beams.
one issue i see is the long gen2 inlet runners, this isn't ideal for top rpm where your cams are aimed at.
TBH i hope you do make more power than a beams, then i can continue building my gen2 NA head for my 3sgte and not source a beams engine