[SteveM3]

You can't just put bigger discs on. Ebay has new 294mm discs/calipers/pads for about £200. On top of that you would need new caliper carriers, probably £20-£30 used for a pair. The protection plate (what I call the dust shield) is the same so that doesn't need changing. There is a world of possible options, I would go for better pads and discs and reconditioned calipers. For what it is worth I think it is worth doing better brakes gives you increased confidence.

 

[SteveM3]

That was just my brain storm. Later i have checked what i need to buy and like You said, it's better to spend few extra quid on replacements than buying cheaper bigger discs to gain few millimeters extra.
The choice is for Brembo drilled discs and ATE ceramic pads on front and solid discs with same pads on rear.
I have them installed on Insignia Estate and they doing really god job on much heavier car like near 2t estate. No fading or overheating.
To be honest, what i want to gain is much less brake dust on wheels.

Any advice?

Red Stuff pads are the lowest dust pads I have ever used. Also after cleaning the wheels use a brake dust barrier like Armour All Shield. One can will last for ages.