Puget Systems does pretty extensive testing. You can look at the actual tests they've done, try out their sample project that they're testing with, and see the numbers each processor got. I'd do more research on their site than just that one page. It's full of useful information.
That said, yes, focusing on the CPU is more important than the GPU. Single core clock speed is currently more important than the number of cores. The AE team has publicly said that they're working on making AE's renderer more multithreaded, but until that update comes, single core speed is the most important thing.
You definitely want at least 32 GB of RAM - I'd get 64, if I were you.
A decent GPU helps for sure, but you don't need to go crazy here.
And, yes, you definitely want a separate SSD/m.2 drive for AE's cache. I'd suggest at least three drives. An SSD/m.2 for OS and programs, an SSD/m.2 for AE's cache, and another drive of any kind to hold project files, rendered video, stock files, archives, etc.