Just get rid of temperature and weather, you should be fine.
I keep seeing this advice and it keeps failing to do any difference to me. There's not much of temperature evaluation if you don't pump magma around map unreasonably, which people with slow machines tend not to do.
One thing you can also do to speed up the game is to end world gen before it goes on too long.
Stop it around year 50 or earlier.
Another saying that isn't quite true, longer history only slows down the game when it is referred to. That is: when the game is loaded and when historical events get placed on images (you can even see freezes when engravers work).
Another Mod that not only adds gigatons of content, but it also increases FPS really well: Masterwork.
I keep seeing this as well, but the only source of this is Meph himself. And I can't see how assigning the same attributes to every functionally identical material would make the drain caused by the storing and processing of the said attribute, leather names being the example. To me it appeared to run slower, just as any other extension mod.
As for the .31.18 vs .34.11, I used to have 100-150 dwarves fort back then and I can't get more than 90 before fps drops below 30 now. Addition of new stuff slows game inevitably no matter how effectively it's coded.
Though I can't play old version now, without all those new features.
If you wish to stick to .31.18, there was an "Intensifying mod" for it which simplified anatomy and made contaminants boil away immediately and thus quickened the game up a bit.