Plugs,plugs.OK:

For non-turbo head (std. plug):
Novarossi C6S mediumplug, for cool days
Novarossi C7S cold plug, sunny and hot conditions
Novarossi C8S verycold plug, for extremely hot days or high RPM running.

For Turbo head engines:
Novarossi C6TGF hot plug, for cool days
Novarossi C7TGF medium plug, best all round plug for most conditions
Novarossi C8TGF cold plug, for extremely hot days or high RPM running.

Don't have experience with other brands, sorry.
AFM