Updating a 1Z 1.6 FSI - alloys, stereo etc.

I've lurked for a while - here's my first post.

Firstly, thanks to everyone who contributes here - this place is an incredible resource and has been invaluable for me.

I'm picking up a second hand '07 1Z 1.6 FSI Octavia Amb. in Satin Grey on the 1st, having rescued it from a forecourt before the rotors and pads rot to nothing. Aside from exposure-based deterioration of AC, cooling and brake system, professional and detailed inspection of the car has revealed no major issues and very few minor issues, all of which the dealer has agreed (in writing) to resolve before I purchase it.

As a reward for its patient wait, I am keen to supply it with some much needed upgrades to

1. the stereo system:

currently fitted with a single DIN Blaupunkt :( ) -> Bolero? (no need for Nav, but Bluetooth would be nice). Does anyone have any aftermarket suggestions that fit harmoniously with the Octy interior?

2. the wheels and tyres:

currently steel and (loud and unevenly worn) Conti winter tires -> Pegasus alloys (2nd hand), and any tire brand suggestions? I had the Pegasus alloys on my last Octy ('06 2.0 Sport), and I think they look sharp. I am in Denmark, and road surfaces are typically rough (=noisy) but not potholed.

3. Brake calipers/underside:

there is cosmetic rust on the underside and crud on the calipers. I would like to scrub this off with a wire brush and apply rust converter. Aside from being a dirty job, would anyone recommend getting said done by a professional instead due to a risk of damage, making the issues worse, etc. if any?

4. Exhaust tail pipe:

There is what looks like a removable bumper plate to expose a cut out for a (fake) double exit tail - for purely cosmetic reasons I am thinking about getting something like  p/n FDC609004 or FDC610004. Does anyone have any experience retrofitting these, and/or pictures of a finished job?

5. Jumbo box:

There is none, and I would strongly consider having one fitted in the Czech Rep. - a spare 12V (and possibly AUX) would be really useful, depending on compatibility. Thoughts?

6. Just like in my '06 2.0, the leather handbrake sleeve (full length, not jumbo box shortie) slips on and off. Is there some reversible way to secure it properly?

Thanks and thanks.