Sell the Corolla since you will get a better value out of it betting its a Toyota. Also as you mentioned you have invested sa Getz. So might as well keep your moneys worth since what you save on fuel can be placed for maintenance assuming the Getz has a higher maintenance cost. Also a smaller car maybe more easier to drive for your wife. At least you have variety in your garage. I seldom see 2nd Hand Getz for sale so people do keep them longer. But thats just my observation only.
Sell the getz. Keep the corolla. Ask yourself, how many surplus shops do you know of that sell parts for the getz vs the 2e corolla? Besides, if the 2e conks out, you can always buy a surplus vios engine