With the tuneup I'd go AC Delco. As for cleaning out the intake and injectors...try running a can of SEAFOAM through the brake booster hose with the car running before you go to change your oil. It says to put it in your gas tank but it won't work as well just being ran through there. I ran seafoam in my Xtreme and my parent's Yukon and both times you could tell how much smoother it ran, at the time. I would recommend it to anyone, especially anyone who has racked up a few miles on their motors. The thing is, it'll make your motor want to die out but it's no big deal, that and since it's burning up all the gunk in your intake you'll definitely see it coming out the exhaust. Your neighbors will think you blew up your truck or if noone was paying attention and just walked out they'd think you just did a giant burnout. lol. It does help though.
As for the injectors, if you're going to replace them, and don't want them to potentially clog up again, don't replace them with what you have already. Buy the MPFI injectors. They're the non-poppet style and they won't clog, so you won't have to ever run into a mysterious misfire if one of those poppet style injectors clogs up. I'm running the MPFI injectors on my Xtreme and have had no problems whatsoever!