I guess all I'm saying is it would seem a likely and logical extension to the the "best braking system on a 4 door luxury car I have ever driven" to include a DOT4 fluid. That's all I'm getting at. I'm just can't imagine what the trade study bullets were that spit out DOT3 fluid is the right answer. Who knows, I think the Z06 comes with DOT3 as well.The differences? - Wet and dry boiling points. Some fluids have higher tolerences than others. When you are running a 2000' straight at over 130 mph, and have to turn hard into a 90* left hand turn at less than 30 mph, you hope you have a good braking system. The stock fluid works well, but when you are hitting that left hand turn for the 10th time in the last 20 minutes, and have 12 other hard corners added into each lap of your track session, you want insurance that the fluid won't boil or allow water in. That is why track day guys change the fluid. For repeated hard sessions in 100+ degree days put in something with higher stress tolerances.
For the everyday driver, the stock dot 3 works fine. Cadillac and Brembo built the best braking system on a 4 door luxury car I have ever driven. This includes BMW, MBZ, Audi and many sports cars. There is no reason to complain about the brakes as they come stock. I just appreciate a little extra insurance for my track addiction. As for the G8 brakes - I'll take the V's brakes with dot 3 every time if I had a choice.
Thanks. btw, it was nice reading about your experience at the CTS-V challenge. Once in a lifetime man.....I'm not speaking from much experience (only 1 track day) but I'll pass on what the V designers, engineers and techs recommended before my day at Monticello. They told me to get ATE Super Blue dot 4. It was a pain in the butt to find. It's readily available on the internet, but I needed it ASAP and it was hard to find at a retail shop and more expensive. If you have time, get it on the internet. I'm sure the others were fine, but I bought 2 quarts and had the dealer completely bleed, flush and fill. They said a "typical" flush only gets about 80% of the old stuff out. I'm not exactly sure of the process, but they spent a little extra time and effort to get all of the old stuff out.