i run on 18s at the mo with a bit of poke.....i ve opted for 225/45/18 over 8.5 front rim with off set 20 +25mm of spacering = -5 and 245/45/18 over 9.5 rear rimwith 20off set +28mm of spacer = -8..
imo gives the car a nice stance and poke.must add that the rear arches have been roll to accommodate
thinking maybe 235/35/19 on the front for my 19s on 8.5 rim and 255/35/19 rear 10.5 with 255/35/19 with 20mm spacer and 15mm front which will = +5 front and +15 rear but still give poke.