Hi Sourabh
The ground clearance of Yaris is at par with Honda City, if not slightly more when fully laden. I've not really found any major issues, infact have not scrapped any of the speed breakers yet. May be slightly shorter wheelbase helps in some way.
My parking has a ramp, and the car doesn't really scrap that has well.
The only issue could be the approach angle, as the Yaris has some flaps at the bottom of the front bumper, my guess is to assist in aerodynamics... and these flaps might brush with high speed breakers or ramps if you are not cautious about the approach angle. Not a major issue at all. Have really started enjoying the smallish turning radius of the car, makes life easy in the City.
Also, got hold of an OEM dashkit for Yaris.. and was able to upgrade the dashboard player to Blaupunkt Osaka 760
(Link) .
It supports Apple Car Play and Android Auto.. and kind of completes the car.
On FE front, getting an Avg. FE of 11 KMPL in 100% city driving with AC ON all the time..
Cheers!