Hi Mate,
The greenstuff is rated at 600-ish deg C, while the redstuff is rated at around 750deg C.
Have a look at http://www.ebcbrakes.com/greenstuffinfo.html for greenstuff info, and
http://www.ebcbrakes.com/redstuffinfo.html for redstuff info on these pads.
The redstuff is made from the new 3000 series compound.
Some people who has used the redstuff likes them, for the price they gave value for money, and give better feel than the greenstuff. I had greenstuff when I had my R33, low dust, and good daily driving performance. For spirited street drive I'd recommend redstuff based on what people have told me regarding their first hand experiences.
Red should be enough for once in a while club track days (4-5 laps), and hill climb events. But if you're after more racing edge, e.g. for downhill race motorsport, then I can source you some yellow pads or even extreme blue racing pads, but these cost heaps and are R 'Racing' rated compound which RDA told me need to be warmed up a bit before you get optimum performance from it...
So IMHO I won't recommend it for street cars to use anything above redstuff, as they also cost more and probably overkill on most street cars.
Hope that helps...