tarox 6 pots bolt on as long as you have 17 inch alloys with correct offset. Currently circa £1800 for a kit so not the cheapest option but do bolt straight on, wit braided lines etc. Audi S3 / TT v6 calipers bolt on & allow for bigger disc but only 2 pot. They do work well though with the 2 piece discs. There are kits available for brembos from other cars to bolt on which act as a spacer but most won't fit under 17s (other than the older AP 4 pots from earlier
ibiza) so you will then need 18s (or at least thats my understanding as not personally tried this option). I would personally start with flushing the brake fluid & putting a better grade of fluid in there. 150hp combined with the light weight of an
ibiza shouldn't require much stopping power but its good youre thinking that way unlike some that slap big turbos on & then cook the brakes within few minutes of spirited driving