Think about what I just quoted of what you said ^^^ LOL. Changing parts IS optimizing the build. If I didn't, we wouldn't know the 750 DP would outperform the 770 VS on my Duster, now would we :D
No it’s not. Your changing parts, your aren’t tuning anything. Don’t confuse the matter. If you can’t pick a set of heads or whatever...and your carb example above is lame. No carb is going to change converter need like that. If you go from a single 4 to a TR them you’ll need a different converter, and a different cam.
You come up with some off the wall, wacky crap for sure.