Well honestly I'm by no means an expert on this. But trust me, bit of soundproofing with better audio quality, and you will find what you've been missing. I simply got front components and rear door 6.5" coaxials (both Hertz Deici) and Focal Auditor 6x9 for rear shelf. Using OEM head unit so these speakers can handle a lot more. No amp, but combined with bit of soundproofing, this is already more firepower than I need.
All I'm saying is suppose your speaker has already gone bad, it's a great opportunity to get better speakers rather than replace with same OEM one. I hear many people say that Civic X has a great stock sound system and mine now feels crappy compared to Accord's. For starters, if you simply get yourself some decent components for front doors to start with, you will immediately feel the difference.