Hello.
I run my `93 GK76A for few years with iridium NGK (CR9IX),but my mechanic told me that this sparks work well on high temp. So I wanna try with the regular sparks now but which one-CR9EK or CR8EK?

It depends how much build up you have on your plugs, if they are prone to sooting you have to increase the temp of the plug by one. I would have guessed that you in Bulgaria would be fine on cr9ek.
'EK' plugs fire on the top of the plug and not like a conventional plug, and have 2 electrodes which take up a tiny bit more combustion chamber volume. You may lose a small amount of power using cr9EIX.

Gracias moforockband .I get cr9ek and already got 2k km.