Replacing original spark plugs

[chromebumpers]

My 5.3 ltr. is approaching 90K miles and I'm thinking somethings should be replaced. Should I replace the plugs for the exact plugs it came with or is there an up-grade? Besides the oil and filter, air filter, plugs what else should be replaced? (I cannot find my owner's manual or else I would look up the scheduled service at 100K myself).

 

[grumpyvette]

My 5.3 ltr. is approaching 90K miles and I'm thinking somethings should be replaced. Should I replace the plugs for the exact plugs it came with or is there an up-grade? Besides the oil and filter, air filter, plugs what else should be replaced? (I cannot find my owner's manual or else I would look up the scheduled service at 100K myself).

if you post very clear pictures of all the plugs I can tell a good deal about the conditions in the engine during combustion.
obviously , oil and fuel filters need changing, air filters also need to be either replaced or carefully cleaned, and a radiator flush and new coolant would be a good idea, belts and hoses carefully inspected and Id suggest closely inspecting the battery, battery cables, ground connections, replace any anode in the coolant system. and Id top off the power steering fluid, replace the trans fluid if its an auto trans and grease the ball joints, and inspect the U-joints