The first car engine I rebuilt was a 1978 Pontiac 400 Trans Am, with no service manual. I have rebult everything from air cooled VWs to V12 Mercedes. The FSM for the Vg30de is actually pretty thorough on assembly and inspection. There are no trap-door oddities about vg motors. The technology is 30 years old and very commonplace now. Of course there is no substitute for experience. But, like anything else you have to start somewhere. A little fear of the unknown is good but you can't be afraid to try. Just ask for advice and get a friend with knowledge to help.