The old underpowered woofer theory pops it ugly head....keep the signal clean and you should be fine with most any output level. The 38hz tuning is a bit on the high side. probably will have some good SPL but some loss at the low end due to the higher tuning frequency, will also keep the driver excursion down (hence no really low notes) Probably why Kicker recommends it, keep the coil in the gap.