I'm looking at prepping my 8L S3 for a trackday and am starting off with the brakes. I will be fitting X-drilled discs front and rear with ferodo ds2500 pads. My issue is with the brake fluid. I have had it suggested to me to upgrade to dot 5 fluid to cope with the greater temperatures that the fluid will have to cope with but dot 5 is silicone based so it is hydrophobic (does not absorb moisture) meaning that if i drain the current dot 4 (which contains an element of moisture) this moisture will not be absorbed by the dot 5. Will this cause any issues being that it will be such a small quantity? Also i've heard that dot 5 isnt recommended for modern abs systems? any reason why? and also that it isnt the greatest for normal road use. so overall is it worth changing or should i just give it fresh dot 4? any advice would be appreciated especially if anyone has actually swapped themselves!