In that case, you're likely going to need injectors that'll flow 800+ cc/min. It really all depends on how much power you're realistically going to try to make. If you're looking to push that turbo hard (30-40 PSI), then go ahead and get 1000cc fuel injectors... but if you're going to stay in the 18-28 PSI range, you should be fine with 750-850 cc/min.

The part number for ARP cam tower studs is: 141-1001

There is no part number for 1/2" ARP head studs, because they don't make a kit. You have to call ARP and order them ala carte, meaning you need to take measurements yourself and tell them each individual stud, washer and nut that you need.

I want to make sure you understand that you probably don't even need to go through the trouble to install the bigger head studs for the setup you've described. The standard 420A head stud kit that ARP makes works GREAT. It's only neccessary when you have extremely high cylinder pressures due to very aggressive valve timing, aggressive ignition timing, high boost, and low RPM nitrous injecton... all together. Boost pressure alone doesn't push the cylinder pressures to extreme highs, it's in the tuning. If you were going to be injecting nitrous too, then I'd say go ahead and machine the parts for bigger studs. Either way, the chances are very good that the head will lift regardless of what you do. Any tiny bit of detonation that occurs at that level, will at least pop a headgasket FAST. It's all part of having lots of horsepower with a small motor. No one just "runs" a big turbo four cylinder at 30 PSI boost. They "maintain" it.

If you're going to install the bigger studs anyway, then you'll need to get new head alignment dowel pins, and bore them out in a lathe with a 0.515" drill bit. You'll need to find a machine shop that can fixture the block perfectly level, drill it out, then re-tap for the larger studs. It's not easy.