[pierreye]

Just done the upgrade from stock BMW HK speakers to Faital Pro 4FE32 and Eminence SD28 tweeter. I'm using 2nd order crossover around 3khz. My initial assessment is for lower volume, I can't hear much difference compare to stock speakers. But once I turn the volume up more than 50%, I can hear the new setup sounds more compose and willing to go louder without distortion. Normally for stock speakers once I hit 75%, will sound harsh.

Note that if you want to use 4FE32 for center channel and rear channel, you need to cut both lower mounting arm.