Oh, puhleez!
Ask 100 people on the street if Giuliani is running. About 20 will say "Julie Who?", 79 will say "Heck, yeah!" and 1 will say "I'm Rudy's Mom, and he hasn't said anything to me yet!".
My point is he won't peak early if he doesn't announce early., The speculative fever will only grow and if he times it properly he can go into the primary season with a huge, HUGE lead in the polls.