The warranty is what you're paying for, and you need to decide how much that is worth to you. Replacing the engine, whether you choose to do it at a dealer with GM parts or somewhere else with aftermarket, is the least cost effective but will have the best warranty and everything has been checked out in the engine as is good. The GM engine will get you a 3 year and unlimited mileage warranty good at any GM dealer in the country - that's what you're paying for. Aftermarket is probably still 3 years but may only be 36k miles or up to 100k (some may offer more, I haven't checked every single place in the world that sells reman engines). If you fix it and replace the cam and lifers at the dealer with the stock parts, you get 2 years and (I'm pretty sure) unlimited miles on just those parts and nothing else will be covered. You could do the stock parts replacement at an aftermarket shop and get 2 years on the parts still, but you'll have to pay the labor. With the AFM delete (which will be an aftermarket cam regardless), you will likely only get 90 days or no warranty at all but will be much cheaper and, in theory, last longer.
