Just use a quality synthetic DOT4, (i.e. MOC). I was told by my buddy who is a hyundai gold mechanic that the racey fluids don't work well with Hyundai's ABS module. They actually can cause air in the system from the abs module. Again there is no way to confirm this but this is one opinion from an experienced person.
all brake fluids are hydroscopic, it's part of their charm.
Like Thumb5 said, a quality DOT4 (not DOT5!) is all you'll need. Changing brake fluid is part of owning a car and if you want high performance braking where the fluid will get hot, you just have to accept that you'll be changing it often.
Some brake fluids can cause foaming in ABS systems regardless if it's a Hyundai or not, especially since it's not Hyundai who makes our ABS/EBFD units, Bosch and Mando do.
Hmm. I drive very aggressive stints for 20-30 mins with heavy braking which can lead to very hot conditions. Not sure a Walmart version is what I'm looking for, but then again, my knowledge is limited.
Walmart stocks Valvoline brand brake fluid. It's fully synthetic, too. Same with Prestone fluid, I just prefer the Valvoline because if I recall it has slightly better temperature ratings. Should even list it right on the bottle.
^ is also a massive b*tch to setup on a car that wasn't designed for it, wrong materials can cause fires and 99% of this forum doesn't have the smarts to properly set it up to be functional or the skills with the tools required to fabricate proper dust plates for it.