Solved Laggy Builds
I'm wanting to revisit some of my builds from back in the day and some of them may cause lag with some of minecrafts more recent updates. I am mainly wondering if Lava flowing through my base in large quantities, or a single-line of BuildCraft Pipes are still laggy. I don't know the functionalities/optimizations MojangCroSoft might've made regarding these.
I want to ensure my build doesn't negatively impact anyone else.
while we appreciate you being considerate about it, I don't see anything particularly problematic with what you described. Lava should be fine, especially when static. BuildCraft pipes should have had a performance upgrade, so if those are used reasonably they should behave too. If you want to be 100% sure, you can look into whether Thermal Dynamics serves as a worthy replacement - should that not break the retro of your base.
To my knowledge everything comes down to scale. One of the few things that brought the Ultimate server to its knees was a massive quarry hitting a water pool, causing a gradually increasing water flow over the entire area. Things like that just happen sometimes and it's no problem. But this should be in a whole other order of magnitude than a bunch of decorative liquid in your home base.
I'd say, go for it, the number one cause for laggy builds is and will always be badly designed mob farms.
Have fun building!~