When my stock discs were worn it seemed daft not to upgrade when to do so was cheaper than staying stock.
Big Phil (a Guru trader, sadly missed, who really knew the Z) sold me EBC turbo-groove as a good fast road disc. One other reason they are good is that the dimples match the Rays but they give me no complaints.
I have always loved Ferodo pads and DS2500 do not disappoint. Just when you thought the fade would start, they bite really hard. They are a good fast-road choice and late breaking is always good for a squeak and a thump from the missus, although the be fair you don't notice you are doing it, you just get used to how good the brakes are.
Nevertheless, if tracking, Phil recommended the DBA disks as truly excellent performance and quality - but now we are talking a little more money than stock replacement!