Sir,
what is RMS your subs having???
Your amp is give 800 Rms @ 1ohm and 1600 Rms @ bridged mode!!!
Its a good enough amp,but i ensure you that it is hardly able to run 1 spl of 3000 watts!!!
2 x 3000 Watts spl means 2000 Rms and your amp is giving them just 800 Rms @ 1 ohm!!!
You system is surely under powered!!!!
Your current setup is good but if u later want to upgrade your subs then upgrade your amp also!!!
Regardz!!!