Should I get 32GB CL18 or 16GB CL14 RAM?

Get the 32GB CL18 kit unless you’re benchmarking memory for a living. The real-world performance difference between CL18 and CL14 is tiny — single-digit percentage points you won’t notice — but running out of memory with 16GB is a real problem for modern games, browsers, and creative work. Capacity wins over latency for most people.