The US Acoustics will give you the best "bang for your buck". They are actually really good amps, just overlooked. The alpine is a nice choice too... but both the US Acoustics amps will give you more power... and no, the 85x4 is not too much.
Ive never heard of a DVC Kappa Perfect. They only come in single voice coil design. You may want to find a JBL BP600.1 to power it... those subs are very power hungry... and they can take a TON of power... so dont be afraid to go with something bigger if you can find it... maybe a US Acoustics USX or USB-2150... just to match the other amp.