I can't thank you enough for this. I've never played EC's version of this world, because it was recommended I try your save first. And it ran great from the get-go. I have a gaming laptop and your save along with Nraas has IP running SUPER smooth. Smoother than some EA worlds, even. I'm 3 generations in, with a bunch of added custom Late Night venues, and it's still running great.
My kids, who DON'T have gaming laptops, also have no problem running IP. My youngest daughter even uses a $200 "black friday special" laptop from 3 years ago (truly bottom-of-the-line) and while it doesn't run smooth for her, IP is now stable and playable, no worse than any other world.
Only one thing I needed to change was the Medina house. Something about it is bugged beyond saving, it's like the sims don't know where they are in relation to the rest of the house. Weird wild stuff happening there. And the Amigos house, they get stuck under it sometimes and they compulsively try to play catch when they don't have room on the lot, but I moved them to a houseboat. Those are pretty much the only things I had to do to make me the perfect "starter" save for IP.
Thank you again for sharing all of your hard work with us. :)