Do a search on this site Stupa - some blokes have done pretty good writeups on what you plan. I'd love to go manual but I know I'd kiss my license goodbye.
Good Luck.
Edit...just did a search for "auto to manual" on this site...best one after a quick look was: http://forums.justcommodores.com.au/showthread.php?t=36375&highlight=auto+manual
Yeah Ill probly end up walking again, but then again if I stick with the auto its gonna die soon, But more importantly is there anything that is not interchangable between the vr and the vs. Being a different engine and all.