If you're serious about considering injectors and you're planning a turbo rebuild or replacement, upgrade to a Garrett GTP38R and call it good, the you're good to go with about any injector you'd like all the way up to a 250/200. The only problem you have is that with an '02 you have PMRs or Powdered Metal Rods, which most guys won't push past 400hp due to a high failure rate. You can push the PMRs farther but it's not a good idea if you like having a running truck.
My plan is to run a 38R with either 175/80 single shots, or 200/80 hybrids. The consideration for me is the ability to run any stock or readily available stock HPOP. Hybrids take significantly less oil volume than singles or split shots. The only drawback to a hybrid is the loss of injection pressure, peak attainable is only about 16,000psi vs 22,000psi, and with the larger nozzle the atomization quality is slightly lower. The thing they don't seem to do with 7.3 injectors that they do with 12-valves is increase the number of holes as well as alter the size to maintain better fuel atomization.
250/200s with a 38R will make 550hp+ pretty easily, the 200/80s will make 500hp pretty easily and 175/80s will make 450hp. With PMRS, you could de-tune 175/80s to make 400, but the temptation to make more can get you in trouble. A more appropriate choice would be a 160/30, it can make a bit over 400hp, but you'd have to try harder and push for it with your tuner. Also, the 160/30 can be run with a stock turbo and an upgraded compressor wheel and maybe the compressor cover.
With over 150k on the engine if you plan on injectors and turbo upgrades, you definitely need to do valve springs, and with valve springs you need to do pushrods. Being it's a PMR engine, you'll not need to do head studs or anything radical, you'll break a rod before you hurt a head gasket. And as long as the high pressure oil system is healthy, you should be in good shape, but if you end up with HPO codes after tuning or running injectors, you'll want to look into the IPR and possibly a fresh HPOP.
The Current Truck (Oct-2013 to Present):
1999 (Early) F-350 Lariat, CCLB, SRW, Black/Tan
7.3L Powerstroke, 4R100, 4x4, 3.73, 37x13.50-18s, '05 Axle Swap, 6" Fabtech lift, GTP38 "D66" turbo upgrade, SCT 4-position chip with custom tuning by me, Straight Piped 4" down pipe through 5" dual stacks, N-Fab full length triple steps, Pro-Tech cab guard and tool box, louvered 5th wheel gate, Hella 500 Fog and Driving lamps, much more to come...
The one I'll miss, (Mar-2009 to Jan-2014):
2000 Excursion XLT 4x4
6.8L V-10, 4R100, 4.30, 285/75-18, 271whp / 388wtq
The one I won't, (Jul-2005 to Sep-2012):
2005 F-350 XLT, CCLB, SRW, 4x4 FX4
6.0L PSD, ZF-6S650, 3.73, 35x12.5-18, 4.5" Lift