I have this Pioneer fitted in a 2011 Civic along with some kicker KS components in front door and doors have sound deadening, but got to say really not impressed with the sound quality. I have to turn the bass down in the EQ or it really distorts at just over a quarter max volume. On tracks that don’t have deep bass, but punchy bass, you can turn the volume up and feel the punch. But deep bass, you can only play at low volume, and even mainstream tunes like 80s songs, there’s just no ‘warmth’ unless you turn volume down and bass up. Guy who fitted it said I need a subwoofer, and I’m sure he’s right. But really did expect for from the £240 Kicker speakers. Not sure if it’s because it’s running from head unit but that’s 4x50w, and it feels like a bigger amp would just blow them. A guy in a civic forum fitted Hertz ESK components (civics need shallow mount depth speakers), and described them as like having small subwoofers in doors, so hoped speakers costing an extra £80 could at least get close to that. So do I change speakers, fit an amp or just get a sub? I’m sure the sub would be most effective, but really wanted to try and avoid fitting an amp, or an amp and sub. That said I’ve had a Macintosh 10” sub for over 10years that I’ve never used. So may as well use it. Does anyone know good software that can calculate best box sizes? There used to be ‘boxcalc’ but not been able to find it recently. Many thanks for help.