Greazzer on here is Da Man for injector reconditioning and he's ABSOLUTELY honest. Great resource.

Also do a compression test AFTER you adjust the valves. Harbor Freight has a compression tester that's good enough though it might not be accurate to 3 decimal places. You're looking for a cylinder that's a LOT lower than the others. Mine are in the range of 285 or so PSI (617 with somewhere over 220K) and I see that as marginal though they are pretty even. The point is that if you have a really low cylinder or two all the tuning in the world won't help. Sooner or later I'll rebuild my back-up engine and get lots more compression that'll translate to lots more HP.

Remember that in a Diesel if you have fuel and compression you have power. Nothing more to it.

EDIT: Should have added that of course everything needs to be adjusted right - pump timing, cam timing, etc.

Dan