"Wouldn't the cheap ring terminal bottleneck the performance of the faceplate?"

I was chuckling hard when I typed that.

On a serious note, hire a licensed electrician for in-wall mains wiring, or check with your local authorities on required permit and inspection. Also, make sure the connections are rated for mains and safety earth, though that isn't an issue if a licensed guy carried out the job. You wouldn't want to void your insurance.