Alpine SXE-5725S coaxial speakers (130x180 mm).

Alpine SXE-5725S 2-way coaxial speakers 5"x7" (130x180 mm).

A custom upgrade will have your system looking good and sounding better. Custom speakers are built to precise size specifications to fit in the speaker mountings of specific automobile models. 
They are an easily installable alternative to factory-installed speakers. Whats more, their performance characteristics are designed to match the interiors of the cars they are intended for. 
If one of these custom speakers fits your car, it should rate high on your list of possible system upgrades