Lower timings and higher frequency will lower your latency which bumps up frame rates a lot so yeah it is a benefit.   4000c16 would be the best from what you picked then c18, the other two I wouldn't even consider.

test

If you want to be cheap and don't care enough to look for results just get a 3600 c18 kit or something.  Overpaying for some old x99 sub 3200 kit is stupid.

ZoranC

DEJ915
If you want to be cheap and don't care enough to look for results just get a 3600 c18 kit or something.  Overpaying for some old x99 sub 3200 kit is stupid.

Assuming same capacity how much of price and performance difference one would be looking at between CL14 3200, CL16 3600, and CL18 3600?

for bdies 3200 c14 and 3600 c16 are both like 220-230 bucks for 4x8 kit, 3600 c16-19 kit is like 170 and 3600 c18 kit is like 160 if you don't want bdies so I'd get the c16-19 ones there, they'll be a little faster even though not able to be tuned like bdies.
 
If you want 4000 though, the ripjaws 4000 c17-18 for 240 is not too bad but still way more than the cheap kits (F4-4000C17Q-32GVKB)