Yeah I have a 3200mhz CL16-18-18-38 kit which I run at 3200mhz CL16-16-16-36 CR1. That works fine for me, I get small repeatable improvements in userbenchmark CPU and memory scores as well as a slight increase in cinebench R15 scores. However if I try for CL15-15-15-35 I can run it stableish however it decreases my CPU scores for whatever reason, I believe this has to do with the secondary timings not being ideal for CL15, or it's just instability though I had no crashes. I tried playing around with secondary timings got lost almost immediately lol, lots of failure to POST. So yeah give it shot but lower timings does not necessarily always mean better performance when it comes to manually tweaking them.
The worst that ever happened to me tweaking timings was failure to POST. But a hard reset would always allow the board POST in safe mode so I could change the settings. Worst case you may have to clear the CMOS.