your royally screwed specially as you have taken the car home....nothing you can do legally as their is no proof. Cut your losses and buy a new set of tyres...if your in syd i can hook you up.
springs are great but the damper comes into play here....but saying that what feels great for us might not be so good for you.
id be going for about what you already have and softening the damper a bit
raise the coilovers if you have them if not buy them and adjust the height... At a guess that car was super low prior to the kit being installed anyway
more info would def help here however you generally have to wind them all the way shut (off) then adjust from there. Depending on the brand/type can be a slight turn of 4 turns to get a single PSI increase