2 front 5 rear is a bad height setup imho.
2.5 finger front and rear will be good.
i had this problem with my GAB too. unlike yours, mine is at the back. i use a 205/45/16. i suspect the width is too big for a putra, until it will touch the outer edge easily, thats y u cant go too low if u use 205mm width. 195mm would be safe in my opinion. but after sent it to my dealer, my problem solved.
i maybe talking crap here. correct me if i'm wrong thanks :)