what really matters is what’s in this pic
http://sphotos-b.xx.fbcdn.net/hphotos-ash4/334895_10151190689483930_1067803216_o.jpg
That’s a DFI injection system and I doubt timing chains will be an issue, because based on the front cover in the first pic it looks like they are sticking with a pushrod configuration. However those are the newer generation of coils. Prior statements preticated on those pics being of what GM actually plans on releasing to the public.