Bigger injectors alone without other modifications or tuning would actually be harmful.
The engine controller is calibrated for a specific injector size. It works on pulse width modulation - First it decides, okay, based on current engine conditions, I need X amount of fuel. Knowing the injector flow rate, it decides, okay, I need to hold the injector on for Y milliseconds.
If you swap that injector with one with a higher flow rate, the engine controller won't know, and will hold the injector open for that same Y milliseconds, which would result in too much fuel. In other words, if you swap a 15# injector with a 30# injector without modifying the ECM's calibration, it will unknowingly inject twice as much fuel. Obviously that's bad.
Fuel pressure works exactly the same. Double the fuel pressure without recalibration of the engine controller, and it'll inject twice as much fuel. (roughly - for you sticklers out there, I know that flow doesn't vary exactly linearly with pressure, but you get the idea)
Besides, unless the stock injectors are up over 90% or so duty cycle, there's no reason to need bigger injectors in the first place.
As far as "evening out lean running tendencies", that's a job for a tuner, not a bigger injector. Correcting from 14:1 to 13.5:1 does not mean you need a bigger injector, it means you need a slightly corrected fuel map. Unless the stock injectors are SOOO overtaxed that they can't even provide a tiny tiny amount more fuel. And I doubt they're that maxed.
In other words, injectors would be useless on a stock motor. Think of it this way - injectors do not MAKE power, they ENABLE power to be made. The stock injectors on the LSJ may be pretty taxed already, possibly only good for maybe 220-230hp. But unless you have other mods that will up the output to that level, upgrading injectors is a waste.
