I drive it on Islamabad express way and Bahria town. I think this problem is not just related to tires. Tell me which other car you drive or used to drive previously and what are you comparing it against ?
On small bumps and pebble my Passo is more smooth its seat and suspension is v soft compared to corolla. But when it comes to big bumps with loaded car corolla rocks whereas Passo fails.
I my opinion Corolla suspension is "hard" and performs "Soft" under loaded conditions.
i hope i am not confusing you any more
P.S Dont waste your hard earned money changing tires. Stick to what you currently have, in any case there is very less to differentiate between.