Irregardless of what size shot you decide to run, if you ever wanto to run nitrous at all, I'd grab up that kit for that price.. that's a steal.
changing the jets will cost almost nothing, they are like 8bucks each.
Get an MSD RPM WINDOW SWITCH(the digital one is 9 dollars more than the 'plug in different modules' one and it is twice as easy to deal with (part number MSD 8969) I got mine from Summitt Racing. Very good insurance for your motor, plus helps you hit the squeeze at just the right time, giving better launches, etc...