Well, if you are considering changing brake fluid you need to do a LOT of research.
As noted above, DOT 5 Silicone-based fluid is NOT appropriate for ABS-equipped cars, and in fact has fallen almost completely out of favor with all performance automotive users. For every good thing about DOT 5 Silicone fluid, there are two bad things, for high performance street/strip/track automotive uses.
Your current choices are:
DOT 3 - the default, works reasonably well, has moderate dry and wet boiling temps, probably adequate unless you are seriously tracking the car and only needs to be changed about every 3-4 years, though feel free to change it more often.
DOT 4 - slightly higher DRY temps than DOT 3, BUT!!! it is worse when wet, meaning that to take any advantage of DOT 4 you need to be flushing and changing your brake fluid every 6-12 months. If you aren't changing that often, use DOT 3.
DOT 5 Silicone - Don't Use!
DOT 5.1 - similar to DOT 4 with more additives yielding higher dry and wet boiling temps, some formulations are stable, and some have the same aging issues as DOT 4. It may allow slightly better performance of very new ABS systems, but this is not a guarantee. Not a lot of experience with this fluid, if you plan to go this route, do lots of research.
As a general rule, changing from DOT 3 to DOT 4 or DOT 5.1 does not REQUIRE a complete flush of the system, just push out the old fluid with the new. HOWEVER, it is a REALLY good idea to do a complete flush. And don't come blaming me if you don't flush and it goes badly...
Changing to or from DOT 5 Silicone REQUIRES a flush with alcohol and checking all the seals, hoses, and other components for compatibility.
One final caveat: Some European cars and accessory manufacturers will say DOT 5 when they mean DOT 5.1. Apparently DOT 5 wasn't ever used much in Europe, so they just say DOT 5, but really mean DOT 5.1. Of course, then some of them DO use DOT 5 Silicone, so you have to check thoroughly whenever you see DOT 5 mentioned.