personally i prefer GT spring front and rear for gti moded engine due to its 20% more stiffness that GL.but if you plan for comfort ride, GL spring would be a better choice. std spring with Tuv, Ansi, JIS etc certificate ensure a lifespan within the weight range but we dunno the previous owner usage. local made spring is usually unexpectable due to no test certificate.if lucky then you got it a good shape but normally it will last for few years only.
in our case, 4 doors GL is a light weight car thus a normal spring is still under range except for low down car profile with soft damper.
if you need a better handling, then consider a gas loaded damper and for 4 doors, install the rear sway bar.