I have a 2400 watt 2 channel Volfenhagen car amp, It only puts out 400 RMS watts @ 2 ohms, Per channel,?

RMS and Peak power ratings are always differant, 2 ohm stable amps double that wattage. i.e. if your amp is rated 100 watts RMS, 150 Peak per channel, it will be 200 watts RMS 300 Peak, usually the amp is marked with the peak wattage rather than the continuous power.This means you can run 100 watts continuous power while being able to push a quick spike up to 150 watts. A speaker matched to this will be rated in peak power normally, but these are affected by how clean of power the amp is pushing, An Amp rated at 100 watts continuous power may only push 60 watts continuous and 90 peak clean, the rest may in fact hurt a speaker with the same wattage claims as the amp, this goes for speakers with much higher values than whats described. Since the gains on the amp can be adjusted at the amp, pretty much any sub will work with it as long as the power is matched. Your subs are not matched together as they are not matched to the amp, at 4 ohms you have 500 watts handling capacity, bridged down to 2 ohms you have 1000 watts handling capacity. You could turn the amp all the way down and test them, paying attention to distortion levels, if you can hear distortion your hurting the speakers. Your head unit might also have a gain control that will further help you drop the power to make it reasonably close to the subs, with the amp turned down this low, you will get optimal sound. But if your not amping the other car speakers to match that amp youll be an annoyingly bass heavy vehicle and wont enjoy the music your listening too!

That amp will be luck to even think about putting out 400 watts rms total. You can buy them at any of your local flea markets. 2 different subs from 2 different manufacturers is not a good idea to pit together it is not going to sound good at all.