I thought that means its rich, because there is so much more gas than air, meaning that you have all explosion of gas, and no air

 

No, you were right an exhaust glowing red would be a lean condition. But the stock headpipe on the z and yfz is titanium. At least I believe it's titanium on the z, I know it is on the yfz. The titanium is a lot thinner than the steel and it's ok for it to glow red to a degree. The dealer also told me I may notice that on mine when I bought it and it would be fine. I also noticed on another post you were going to put an uni filter on and remove lid. Whenever you do anything to increase air flow you have to increase fuel flow or you'll be lean.