New V50 - few questions!

[Paul78]

Just bought a 2010 2.0 Petrol SE Lux in Barents Blue - great car with some nice features. It has a rubber Volvo boot mat, 2 mat sets (carpet and rubber), mud guards front and back, aux socket (no USB), electric seats, heated seats, auto-dimming mirror with compass, auto-folding wing mirrors, full leather interior, leather steering wheel, rear parking sensors, optional extra rear spoiler.

Nicely specced. But no trip computer, no bluetooth, no premium audio system, no rain sensing wipers, no headlamp cleaning system.
Would have liked a sunroof and sat nav and bending lights, but beggars can't be choosers.

Just a few questions if anyone can help:

Wheel nuts - chrome caps missing from most nuts, so I would like a new set of wheel nuts for Zaurak wheels. Do I need to buy a particular type?

No passenger air bag cut off switch - I have a 2010 brochure which suggests it could have been factory-fitted for £25. Spoke to the local dealer and they said it cannot be retro-fitted however. Is this right?

Are there any nice tips or tricks for using the aux socket other than for plugging in an iPod?

How long do the "rain repellant" side windows last for before they need re-treating? And if they need re-treating, what is the best product to use?

What is the small regtangular black panel next to the front 12V charger? Presumably for switches - but which switches would be there if fitted?

A Garmin Nuvi Sat Nav was an optional extra - is there any advantage in getting the proper Volvo one over a different Garmin or Tom Tom, eg hidden wires etc? I understand there's a kit of some description for hiding wires?

Would it have had Zaurak alloys when new? Everything I've seen about the SE Lux suggests it should have had Spartacus alloys.

Many thanks
Paul