comp 260s are perfect...270s Max....unless your using a blower or turbo...also...the stage 2 heads would be better....again, because your not forced induction....you just wont benefit from stage 3 anything without higher flowing intake manifold and a supercharger/turbo. 

A cam = What mods do you have. 

You dont want a cam if you dont have anything done to your car.

I would concentrate on other mods first. Cams and heads are a mod I would do after you know what power adder you are going to use and have your bottom end built. Full exhaust and a nitrous set up would get you alot further than heads and cams on a stock block and you would spend less money.  

on a modular, the cams a pretty much the VERY last thing you want to do. If you get cams now, and decide to go blown later down the road, you will need different ones.  you will also need to upgrade the springs as well.

nicole is right, figure out what your overall goal is and then make the decision...but if your not going surepercharged or anything like that, then the comp 260s are great, but recommended mods for these are exhaust, cold air intake, and 3:73 gears minimum,

i have the CAI, borla stinger cat back, xpipe, 100shot nitrous, tune, and will be putting on a procharger down the road, but i want everything else done before i do the s/c. and i would like to wait last min on the gears cause last time i did 4.10 on my other car and wish i would of waited longer cause i prob would of done a diff size gear. so i really want to wait as long as possible on the gear

well, first, something as aggressive as a blower/nitrous cam requires gears, typically 3.73 minimum.  secondly, if you install a blower cam which by the way is what you will need) before gears or the blower, forget about driving the car at all until you get that blower and gear setup installed.

there is no cam that will work well in your car as it is now, and when its blown.  Right now, if you were not supercharging it...the comp 270s would work great, as long as you upgrade that rear.  But these will not work when its blown, you will need a bigger more aggressive cam.

bottom line for the gears...go 4:10s, it wont hurt one bit, and you will need them.  you cant go wrong with the 4.10s...i prefer 3.73s personally because my stang sees the highway more than the track.  right now without the gears you are not taking advantage of your mods. 

You should do the gears, then the blower, then the cams LAST