Seriously boring question (I have googled but to no avail)

My front pads squeak really bad when braking gently to a standstill,other than this they seem fine and just passed an MOT with no advisory.I've read about anti squeak shims but it just gets me more confused.Is it common to take a car to have brakes dismantled and cleaned out as I'm assuming its just dirt or a tiny stone.It's a standard Hawk Sti,

If replacing pads, is it a no-brainer to pay a little extra for better pads or stick to standard brembo pads?I cannot even find info on what standard pads are for brembos?Can they vary??

Sorry for being mechanically retarded, I'm all ears and desperate to learn though!!

Cheers

 

I'm only guessing they are the fronts,I have a circular mark on the front discs too for further indication its fronts