Ok first thing, if you are interested I am selling my comp cams stage 2 with Phase limiters and Ford bolts to do the job. go in the market place to ind my ad.
Secondly, I suggest you to go with stage 2 instead of stage 3. Stage 3 will kill more of your low end torque. That's why I was going with them. Don't forget you are not always over 5000 rpm all the time so it's a good thing to not scrap the low end torque.
Actually, if tuned right, the stage 3 cams start making power around 3900 rpms. Check out the dyno sheet posted on page 7 of this thread. Cobra jet stuff, with full exhaust and stage 3 cams. Tuned by Revauto.
I think Adam@RevAuto or Shaun@AED can get very similar gains out of any sort of cam swap be it COMP stage 2 or 3. Or JPC Regrinds. Alot of the way they react is based on their tuning. Just FYI.