Stock brakes are ok but a lot of members went up a size. I used N14(1.6) and found a big improvment in feel and the amount of pedal pressure required.
Some members have even gone larger although personally I think that's overkill for a road going car.
i find stock brakes to be very good as long as the discs are,nt scored, and i tried the vented almera 1.6 ones on my old super s and found no difference personally, 3mm bigger aint they (but i guess they would suffer less fade)
I also used the N14 calipers. Pretty easy bolt up but wont work if you still have 13inch rims, well you can , I did but it's a very tight fit. You cant get away with it with anything bigger.