Do 166 Brembos fit in the Fiat Coupe under the 16 inch alloys? The calipers look bigger than the Alfa GTA ones and usually go for cheaper.

They would probably fit under 20vt 16" rims but why would you want to fit these?

Sure? From my other car, 300 mm discs fit in a 16" wheel and the 326 mm discs need a 17" wheel as a min. Can't see the FIAT being much different.

Spend your money on decent discs and pads, rather than just fitting bigger discs and calipers.

There is nothing wrong with the OE Brembo calipers as long as they have been maintained properly. Once you've got to the point where the brakes can lock the wheels, what is the point in having bigger discs.

Even if the 330mm discs fitted inside the OE wheels (which I doubt), you would simply end up reducing the airflow even further (on brakes that already have compromised cooling on the inside face of the disc)

I have a pair available and its cheaper than the GTA caliper, also I heard it uses the same pads as a Mitsubishi Evo so finding pads would be an easier affair.

What are you upgrading from? Using 305mm rotors and 166 calipers is like reinventing the wheel for no gain. Larger rotors probably wont fit.

Pads are easy to get, even in Australia 20vt pads were available off the shelf, same as many other cars.

think you need 17 " wheels for the bigger discs