I also received a recall notice on my 2001 GMC Duramax. According to the letter the fuel injectors need changing only if you see a loss of power, hard starting and the SES (Service Engine Soon) light keeps comming on. If you don't have any symptoms don't do anything. GM has also extended the warranty on the Duramx to within 7 years of purchase date or 200,000 miles, whichever comes first without any charge.
I currently see the SES light comming on only after stopping for fuel while trailering and I forget to let the truck idle for over a minute before shutting it off. The light goes off as soon as we reach highway speed after entering the interstate. I don't experience the problem when I let the engine idle before turning it off. Letting the engine idle after a hard pull lets the oil in the turbo to cool, according to Trailer Life. If you don't let the engine idle to cool the Turbo the oil absorbs a lot of heat and could harden inside the Turbo, again according to Trailer Life.