Hey, welcome to the org
Yes, you need an intake and to at least remove your cat (if its still there) and muffler to run a chip. I would suggest going up to a 4" exhaust, but if money is tight, save the money for good tunes and just straight pipe what you've got.
As far as the intake, there are a lot of good expensive ones out there. Again, if money is an issue, you can easily do the diy 6637 intake, a lot of guys have and are happy with it.
I would also suggest getting guages before tuning, egt is a must as well as tranny temp if youve got an auto tranny. Boost is fun too. Don't skimp on guages, get good ones or be disappointed. Use some of the money you saved from the intake and exhaust diy work on good guages.
Once you get the intake, guages, and exhaust taken care of, then you can start looking at tunes. Only go with custom tunes, or not get the full potential of the truck and toast your tranny. PHP (Power hungry performance) is who I went with, but there are a couple other guys out there that do custom tunes. I've been extremely happy with my PHP tunes and they are great people to work with.
If you have any other questions, don't hesitate to ask.