Hi all, hope someone can help answer a few technical questions,
I have been researching on here and elsewhere, and before i order the parts, wanted to make sure they are correct.

i have a parrot ck3100 kit.
i fitted this, along with a few others, years ago, and have decided to put it into my 2009 a3 with standard double din.
i have mostly forgotten how to go on with it, but am sure it will come back to me when i get going.
so - heres what i have so far:

Keys, i need four?
like these?
AUDI DOUBLE DIN CD RADIO STEREO REMOVAL RELEASE TOOL RELEASE HEADUNIT KEYS PIN | eBay

an SOT harness, there are so many, but this looks like it?
CT10AU01 Parrot SOT T-Harness Adaptor ISO Wiring Lead For Audi A3 (2007 ) | eBay

and basically, thats all i need?

However, after looking through all the different threads (not many actually) i saw you can get a multican so the multifunction steering wheel can be used.
Parrot MULTICAN Steering Wheel Control Kit UK
looking at the reviews though, there are only 2 on here, and both said the local engineer couldn't get it to work, and are from 2009.
i can't find any installation guides, or mention of it on parrots website.
i have found one instance of it mentioned in a 'parrot uraguay' page, but the manual has expired.

my questions for this are:
is it worth it, and what are the benefits?
I'm guessing i can use the volume buttone on the steering wheel, and also the start and end call buttons?
and if i fir the parrot ck3100 for now, and decide to add the multican at a later stage, will it just plug into the existing wiring?

thanks for making it this far