So, if I were to replace my injectors with some new bigger ones, do all I need to wrry about getting are nozzles, or are the injector bodies important also for reliability? The reason I ask is all I can find to buy are labeled as "nozzles". So are the bodies of the injectors not such a big deal as the nozzles when it comes time to need replacing?

 

NO You must send them in for testing internals wear out with the stock fuel filter.
Call Todd at T&C Diesel Google him! When you get your new injectors be sure to add a 2 micron filter pre CP-3. Injectors are expensive take care of them. If you get lucky and they are still good then talk about tips with him!