A local audio shop has recommmended the following audio upgrade and I would appreciate your advice please.

JL Audio 300/4 AMP
Focal 165K2 speakers
Image Dynamics IDQ 10"DVC SUB
Crystal Line Translator CL 0.2
Phoenix Gold wires and cables
Fiber Glass SUB Box

Should I keep the stock HU or replace with an Alpine 7997 HU? How much of a difference would it make?

It is not important to me to have a 6 or 12 disc changer.

Thank you for your responses.

 

Definitely definitely definitely replace the stock HU, it will make a world of difference.

Also, loose the CL.

Other then that great choices. ID subs rock, JL amps are wonderful amps, and Focal has some great speakers. Add that Alpine HU and you're set.

 

Very nice choice of equipments but I would suggest more power to the focal 165k2. This set loves power, the more the better. I would suggest stepping up to the JL 450/4 rated at 150x2 and 75x2. Use the 150x2 to run the 165k2 and 75x2 briged for the IDQ 10DVC (two ohm dual VC I assume) and you will have a very dynamic system.