you will see little, if any, difference in performance with your combo with a V2 vs V4....what you will see is cooling problems......to run "in the 10 sec range", you need a little more than you are proposing....like a stronger bottom end to include a girdle and/or steel caps...you will need a bigger turbo, better converter, built rear end (no c-clips), built transmission w/brake, slicks, modified suspension (at least boxed arms, new springs & bushings all around), roll bar, SFI balancer, really well ported iron heads, cam (preferably a billet roller), down pipe, bigger injectors, preferably a digital fuel management system, better fuel delivery system,etc, etc, etc
contrary to what many assume, the average GN is not gonna go out and run 10's with some bolt ons....12's maybe, but not 10's.....so be prepared to spend some $$, to break a lot of stuff, and wind up with a not very friendly to drive car....
you can believe me or not, but I would caution you to listen to those that have been there and no one else
You do have the advantage of good air and sea level, so it "may" take a little less
sure you want to take on that 10 sec big block???