The G23 is the best of both worlds, the ironclad F block and the impressive DOHC H head. I'm working on a G23 build as well, and Roy's CG is testament to the reliability and practicality of the G23. If you don't feel like putting in the time and effort, then just go with the H swap, otherwise, you will feel proud to build an engine from many engines
I first thought the g23 was for someone who just wanted to slap on a head and get more power but after some research I found out it isn't that easy and not that cheap... But I still want to do it because you can make more power than the h22, you'll be proud of yourself for putting in the hard work, you become more open to after market parts which we all know are hard to come by in the 6th gen world.
H-series heads have larger combustion chambers which will reduce compression unless you use higher compression pistons or mill the head a LOT. An 8.xx:1 compression G23 isn't going to do much of anything better than a 9.3:1 F23 unless you boost it.
Check out this ad. This is about an hour away from me. I really really wish I had the money. I'm gonna see what I can do because I can sell my old motor and maybe he'll lower the price if I don't get the transmission. Fingers crossed.