Go for the Redhead, or Borgeson steering box. Just getting stock replacement will leave you with all the same problems.

 

You said your truck is hesitating.. Have you cleaned IAC sensor? As for MAP sensor, unplug it and see if the truck runs any different. If it runs like s**t then you know it was working in the first place. You are installing an off road y pipe so I'm assuming you will be running no cat which will fix a possible clogged cat. Things I would do: clean IAC, check TPS, check MAP, clean throttle body, change front 02 sensor