I am planning to change the front discs and pads on my 2.5. Do I need any special tools, for example to wind the caliper piston back in, or not? I friend of mine recently did his brakes on Octy and that needed (on the rears) a special tool, which he offered to lend me should I do the rears on mine, but not even sure if the superb needs this kind of tool.

You do not need to use the wind back tool for the front discs,I have used a G clamp in the past.