Replacing the front anti roll - Ibiza 1.6 16v

[Ooga]

Hi.
I'm driving a 2007 Ibiza 1.6 16v, with the original front anti roll bar (18mm).
The links are bad and I've checked some replacement options, and seen that Febi has the whole anti roll set for sale.
They have 18mm, 19mm and 20mm (the one you have on the Cupra?).
Will it effect the body roll of the car if I will replace mine to the 19mm or 20mm one?
The car has a tendency to roll.
The part numbers are:
Febi 37090 or 37100 or 37110

I must say I replaced the front dampers to KYB and the springs to Febi ones (front was too low).

Thanks.