Like my tuner told me once upon a time.
You can do it all at once and get a big grin (permagrin).
Once it is gone, all you have is the good running truck, it will still bring a smile to your face, but the "permagrin" is gone.
Or, you can do it in steps and get a "permagrin" in every step.
Exhaust and intake = little permagrin.
Gauges, not really any grin, but good piece of mind.
Tranny, I think you have temporarily taken care of. I have put almost 100K on mine with a tuner plus some, 50K at or near 500HP. Stock tranny with a Sonnax valve and tricumalator springs from David at DI, and a heavy duty TC from O'Reilly's.
Good tuning, do some reading and ask some questions, call and talk to tuners. Find one you like and run with them. If you have a custom tuner that lives close to you, so much the better. Big huge permagrin.
Oil, your injectors will need more oil when you get there, address this one before the injectors. Another permagrin.
OK, now you get into the bucks, and you should do this all at once because it takes a lot of time that will be repeated if you do them seperately. Injectors (Buy more than you think you want, otherwise, you will be going back and doing it again). Turbo, a 38R will get you to your goal, but you are maxed out at that point. Get something with a T4 mount or a Hypermax mount, it leaves you lots of room to grow. I suggest an modded H2E, wish I had gotten a modded one. Headstuds, gotta have them for reliability in my opinion. Valve springs, same reason. Springs also give you a little more confidence when you look down at your tach and see yourself 800 RPM's past the red line. (Trust me, it will happen). At this point you will have to have your chip reburned. There are tuners out there that will offer free reburns for future mods. This is a huge monster permagrin that will take a while to go away.
My only advice to you on tuners. Most tuners use a TS style chip. If you buy a chip from tuner A, and decide you want to try tuner B, if they are both using TS style chips, it is no problem, all you have to pay for is the fee for their tunes, no hardware changes. If you buy from someone that does not use a TS chip, you are kinda wedded to them as your tuner unless you make another hardware change. This does not mean that you will get worse tunes or anything like that, just that nobody else can load tunes on their chip.