I can tell u why. When bringing my friend to book elantra, got few others booking. Disappointed with vios price and specs. Cancelled and booking elantra instead.
Just sharing what I saw.

After changing the front absorber, reat coil spring n absorber i was quiet happy it had solve the fish tail problem, but after i add coil spring buffer it was even better. So for those who want to solve the fish tail problem just add the spring buffer after u have claim the absorber n spring. To be honest i though of adding the anti roll bar at first but not i decided 2 hold on becos at present quiet satisfy with the present setting.