I'm going to go OP and see what the crap is causing this. As far as I know so far, it's a conflict between ars magica and myst.
We have redstone blocks?
I'm pretty sure there's not going to be any block conflicts, so why not do it yourself?
Copy tekkit lite's modpack.jar.
Install CodeChickenCore and NEI to coremods.
Install Tale of Kingdoms and DivineRPG to mods.
Mystcraft isn't causing the lag, dammit. It doesn't work that way, vote, and poof, it's gone. Also, the only reason it lags is memory leaks. I just need to get an auto-reboot thing in place. I forgot about testing.