[aceinc]

I found and am purchasing 2 Ultimax UM 18-22 used subs for 1/2 price.

Does anyone have a recommendation for plate amplifiers, preferably with DSP built in which would match these subs?

Also simplish/cheap designs for cabinets would be good as well.

[JMW73]

It's not a plate amp, but this is what I recommend (I have a similar older model on my DIY subs).

https://www.behringer.com/product.html?modelCode=0106-AAO

And unless you are good with woodworking, I'd find someone who can build custom enclosures for cars and they can design something for you.  I used Next Level Fabrications:

https://www.facebook.com/NextLevelFabrications.LLC

He even installed threaded inserts for feet, and I used the SVS isolation feet that you can buy separate.  My cabinets are DEAD silent.  The ones I attempted to build myself rattled like crazy.