I'm planning on going for around 250 whp. Beforehand, I plan to get a 3" catback and downpipe, Fuel computer, and the FD OEM fuel pump.

I understand that at that point I should upgrade the secondary injectors. Since I don't want to get an ECU just yet(college budget), I plan on getting an Rtek 1.8 to help lean out. The real question is what secondary injectors to run?

Though I much prefer injectors that I can just drop in without any extra work, I understand this:
-In order to run low-impedance injectors, I'd need to get resistors since OEM injectors are high impedance, and so I don't fry the ECU injector drivers.
-Some injectors have a different style of electrical plugs than stock, so I'd need to redo those depending on whatever injector I get.

So tell me, which injectors should I go with and what extra things will I need along with them?

 

I think you have the right idea as far as being safe and addressing the fuel system first.
250whp is going to require a way of tuning fuel AND timing. Realistically you will probably fall somewhere between 200-225hp range.
Do some poking around in the Dyno/Timeslips section and you can find a few stock turbo dyno graphs.

To answer you question for a drop in injector, RC Engineering is a reputable company that has larger OEM style injectors.