When selecting fuel injector size, one has to consider several important factors if the vehicle is to be capable of delivering the necessary fuel, but having enough low speed resolution to deliver good economy.  The first and foremost will be what kind of power the motor is projected to make.  A good port injected engine (e.g. SHO) will absolutely require 0.45 lb fuel/hp/hr for adequate air/fuel ratio at max power.  Also, injectors begin to sacrifice efficiency once they exceed about 70% of the design rating (due to increasing pulse lengths).  Again, also, the injectors are designed to deliver best atomization at the designed pressure, and either raising or lowering the pressure will adversely affect this.  With the SHO, the engine was designed to make 220bhp.  If we take the 24 lb/hr injectors and divide by 0.45, we get 53.3hp per cylinder.  Multiply this by 6 cylinders, and we get 320bhp static (injector open all the time).  We know that the injectors will begin to lose efficiency once they exceed 70% of 320bhp, which yields 224bhp.  Ford knew what they were doing when they selected this injector size.  The factory injectors are not exactly world class items with respect to quality, nevertheless, they suffice for mildly to moderately modded cars.  Cars which significantly increase hp (e.g. turbo, blower) however, will surely need to address this concern.

Using the calculations I provided above, their are three different injector upgrades to consider:

30lb/hr, which yields about 280bhp before slipping (400bhp static), and
36lb/hr, which yields about 335bhp (480bhp static), and finally,
a self modified 30 lb unit which gives 47lb/hr, which yields about 438bhp (625bhp static).

In my opinion, cars with a power adder need to use a 36lb/hr unit for power, motor longevity, and economy.  I have a set on my car which I've used with good results for years.  To spend thousands of $$ on a power adder and not upgrade injectors and use software to accommodate the new power potential is not a wise proposition, and will certainly lead to inevitable destruction of the engine ($$$).