The pump is a piston style. Made to fit tight in the bore and the cold water keeps the gap where it should be. Add heat, expansion happens too much and it'll lock up.
ETA: I'll have to look to make sure, but I'm 99% sure the hotsies heat the water after the pump.
While it keeps the AFM from activating and possibly ending up with a lifter stuck in the on position, it still won't help with the needle bearing in the roller lifters and the soft cams.
You might get away with just resealing the injector. Remove, replace all of the seals, including copper washer on the tip. Reinstall with proper fastener torque.
That looks like it still has the DPF as well. Probably some dumb California rule keeping it from being registered versus being deleted.
Then, it has a butt load more miles than the one he is looking at now.