I'm in the same boat Jay.. I've put a few bucks into upgrading my ESi without going overboard, or going turbo. I've also put too much work in, and I certainly understand your perspective. If you're going to go so deep as to replace pistons.. might as well get the high compression ones. You'll notice a difference. For lifters, springs, retainers, etc.. you will be fine with OEM to be honest. Even with a new set of cams and gears. Unless you go for lumpy cams, then upgrade. Even with little bolt on upgrades like my AEM-V2 Cold Air/K&N Filter, you'll notice a difference.

One thing I like about the NT engine, is that it is a solid and simple platform. When you're ready, I've built mine and would love to help.

On another note, If you're looking for NT stuffs, I've got a spare cylinder head/springs/retainers/cams all OEM if you want. Also got a spare underdrive pulley.