When I took my engine apart with no prior fi and 100,000 miles on it i could still barely see the crosshatch on the cylinder walls. I had the whole thing machined and have eagle rods with probe 9 to1 pistons. Now at 18 psi for a whopping 300 fun filled miles now.
well wouldn't the engine, by 100k+ miles have experienced enough wear and tear on the block, internals, head, etc to be a major cause for concern? i mean even if you do a complete teardown and rebuild, does that necessarily make a motor "good as new"?
i would even say it is better, to have it all rebuilt and machined. i have 80000 miles on it, tom tuned at 65000.
after i get money i will rebuild it with some strong pistons and raise the boost[driving]
Zetec engine are cheap , get your feet wet with the stock engine and make plans for a built engine as you go along , I dont think you will have any issues FI that engine , Do a Compression test and a leak down on it and that will tell you a lot
When the turbo was put on my car with stock eng at 8psi my rod snaped in half and made a very big whole in my block, now i'm running 1bar of boost with a bigger turbo with new internals and i see no prob. I would say it never hirts to upgrade your eng.