Bro boyzone,
If you really made up your mind for sport spring, I would suggest go for Eibach (if it's available for your car model).
Me myself has experienced using it on my previous Proton Satria, and I would say it is the best for overall. Not so lowered, not so stiff and still maintained decent level of comfortability, and quite stable for some "naughty" driving style. Overall, it's best for family setup.
The price would be on higher side compare to other japanese brand or made in kepong/sungai buloh. But, what the heck... You pay once, and you pay for satisfaction guaranteed... Plus, it's compatible to match with your OEM damper/absorber (if you are on budget)...
And NO..I'm not Eibach salesperson...hehehe..just trying to help you...
All the best bro...