Bottoming out is a function of the crossover frequency and slope and power applied. If you're intending to drop in new woofers and keep the factory amplifier you will have no way to control these functions. Also, HD-6MDVC has a very low sensitivity, and I thought they were too quiet even on 225W RMS in my own vehicle. The HD-6MO or HD-M6 mids might be a better choice. HD-6MO may be a 2 Ohm driver. I know the ES-6MO mids, which are nearly identical, are 2 Ohm. HD-M6 is 4 Ohm. No matter what choice of CDT driver, they will all need 100W+ to really shine.