Style chooser

Hi,greetings,I have some questions about coilovers,I was about to change my standard shock to TEIN HA coilovers,Then i test ride on my friend cars with TEIN also,driving performance are smooth while taking curved but,when it come to coarse road,the ride become very harsh,I want to balance beetween comfort ride and lowered car,Is it advisable to use coilover on malaysian road,I live in kl.My ride have 40 profile tyre.