@daniyal
as far as if you have stock engine
145 on 12 inch is very low.....although 12 inch with 145 is stock tyre came with khyber.....but it wont save you at all
on 12 inch rim i will prefer you to get 165/70/12 or 175/65/12
or if u want to go for 13 inch rim
then 155/70/13 or 165/60/13 is good for yr car....
above 165 will make yr car slower....
if you ask for how much bigger size can be fitted in khyber
then in original model which was named MK!...came with 13 inch rim
and sports model with 14 inch rim......an friend is using 195/50/15 in his khyber with stock suspension for more then a year