[Tannaton]

With regard to the towbar - just stick to a good brand like Witter or Volvo original. I *think* it's the same rear end as the Mk 3 V70 - maybe someone can confirm? E-Bay is worth a look as there are many sellers offering kits at good prices. Decide if you want detachable or not...

Yes you can fit it yourself as it's a bolt on job - you may need to cut the bumper though. Best to get the dealer to fit a genuine Volvo electrics kit for a number of reasons. Many people on here have fitted their own bars DIY and then had the dealer wire them in. Some software changes are needed.

It's not a big deal if you don't have 4C - the setup is likely to be between Comfort and Sport anyway.

A very good idea to change the oil in your gearbox and Haldex coupling at 66k, regardless of whether you tow or not. If you're not confident about doing a full change yourself - just do a sump dump and top up about 4 times with 200+ miles in between. Many articles on here about doing that. The transfer box and diff should be fine, but if you are inclined then it's always a good idea to change the oil in them too.

When I suggested tyres I mean more that you are likely to be towing across muddy fields etc. rather than the weather. For muddy fields normal winter car tyres can be ineffective. Pirelli Scorpion Verde All season are a pretty good all round compromise and reasonably priced, I have them on my XC70. However you would need to go up a size to 225/55 R17. I'm sure they will fit okay as that car was also offered with 18" wheels (on 235/50 R18).