I was plan of buying 4 Fi BL series 15's. I needed to know how much RMS wattage could the speakers really take. I am going with the flatwind voicecoil, with the cooling option, and the daily driver. I already have an amp in mind that puts out 4kw. If the speakers can take a little more I will looking into maybe a 5kw amp. I do plan to use a bass processor in line with the amp. I am open to any suggestions.