CSF Miata radiator question.

Couple years ago I replaced my 93 Miata's radiator with a CSF aluminum radiator. I'm not sure why I didn't pay any attention to this earlier but it came with a 20 psi cap. I believe the original radiator had a 16 psi cap. The motor is stock and I haven't  encountered any issues with the car. No leaks etc. Should I put on a lower pressure cap or am I concerned about nothing. TIA

That pressure difference isn't a lot, you should be okay.  My S10 had a higher pressure cap on it without issues, I only changed it as I was already changing the hoses out and didn't know how old the cap was.