from experience, allow me to offer you the advice of keeping all your stock components, just in case you ever want to go back.

when I first bought my truck, I went crazy bolting all sorts of stuff on trying to wake up my little 22R engine, specifically, I installed a Weber 40/40 and a 4:1 header, ditched my cat, and installed a Magnaflow straight through muffler. those are all high rev type upgrades, and not at all what I needed. I was looking for a low to midrange torque boost, not high end power. my point is, think about what you want your truck to do differently or better, and make sure that what you're doing aids in that goal.

that said, be careful with exhaust mods. I've found that the tri-y header design works well in opening up the exhaust enough to breathe at higher revs (3000-3500+), but more importantly, maintains the scavenging effect that the overlapping runners provides (note that it's the same design of the stock manifold? the engineers did that for a reason) I ended up putting my cat back on. why? because while things flowed nicely and freely at higher speeds, without some back pressure, my little 22R lost a lot of its bottom end, the low to midrange torque, which was exactly where I wanted the boost. it felt empty and lifeless.

you can always take the cat off later if you think it's choking the exhaust. for now, try to resist the urge to make all your upgrades at once, and do only one thing at a time so you can really get a feel for what works.

just a little wisdom from someone who's been down that path before, and wasted a LOT of money on things that didn't work, only to come back to moderate upgrades over the stock design.