Weird Neville's SQ 200SX

I feel that a brief explanation is required, being as this site is US based and there's some confusion over the model name for this car.
I understand that in the US the Nissan 200SX is a 2 door Sentra - essentially a front wheel drive shopping cart!
In Europe, Australia and Japan the 200SX or 'Silvia' is something else entirely. It's a Coupe with the classic front engine, rear wheel drive layout. Nissan chose to leave it remarkably raw and as a result it weighs only 1260Kg (2,700lbs). Despite this it has a nice leather interior and Air Conditioning, but that's about all. There's no traction control to get in the way of the fun, but there is a viscous LSD to keep the back end honest. To crown it all they gifted this car the outstanding SR20DET engine. A nice little 2 litre in-line four with variable exhaust valve timing and a Garrett T28 turbo. The upshot is ~200bhp and ~200lb/ft of torque. That's not a huge amount, but these cars are really quick as standard and handle pretty well. The SR engine is also very tunable, with not much money needed to see 300bhp at the wheels.

This car is standard at the moment, apart from an ICE upgrade.

I love this car as it is, but the standard sound system wasn't great. Being as the main opportunity I get to listen to my music is whilst driving, I decided a little upgrade was in order.

Read on for my exploits in turning this car into a Stealthy Sound Quality Demon....