Welcome to the club!
You don't see many in that colour. I like it, especially the blue hood, I can't think of ever seeing one with a blue hood, and variety is the spice of life!
To try and help on the mirror thing - if you mean wing mirrors, I'd suggest you get some which you can attach to the quarterlights with a sucker - they stick on solid but can be removed if you are planning long journeys. That said, they seem to be a bit surplus to requirements on a Jupiter - the field of vision isn't bad at all from the drivers seat. I wouldn't suggest drilling through the wings or doors to fit them - it is a hole that may be a real pain to remove if you change your mind.
If you mean a clip on rear view mirror for the centre of the car, you may well have a tab in the centre of the windscreen to attach one - it comes backward from the centre of the screen on the ones we've got, but yours may be different. Personally I think the vintage ones where a mirror is clipped in are neat and look good, the black plastic ones are ok but not exactly vintage.
If you don't have a tab at all in the centre of the screen you have two options, either a sucker mirror like this:
http://cgi.ebay.co.uk/VINTAGE-CAR-REAR- ... 3802124816 or removing the panels from the inside top of the screen (should be screwed in, normally covered in leather) and then fitting a normal type mirror to the wood behind, or through the covers into the wood.
There seem to be loads of mirrors at autojumbles, but ebay is a reliable source of parts like this. They seem to be more expensive than rummaging through the stalls, but then it is convenient.
For a radio, there's not many that look right and do what modern radios do, CD players, mp3 player hookups etc, I found this one which is a lot more 80s than 50s, but is better than a big black plastic box in there!
http://www.pixmania.co.uk/uk/uk/4100161 ... d-mmc.html - I'd suggest either fitting one inside the glovebox and having a remote control for it, or getting an original (or at least 50s) radio and getting it rewired professionally, however this is expensive.
If you get along to Daventry for the rally you will see every conceivable approach to solving these problems, decide what you want to do, and then ask the owners and do the same. Plus you will get to meet a huge number of members all at once, and this year is going to be a good one with all the GP100 stuff going on.
Jack.