Have had a 986 with factory litronics, and have retrofitted them to my current 986 (and got it through its MOT), have done my own research and spoken to MOT testers, and feel I can speak with some authority on this.
Literally plug and play, albeit you don't get self-levelling and washers (see further below), but contrary to popular belief [and what the internet says], these aren't required for your car to be road legal, in the UK.
Yes.
Fuses A9 and A10 need to be 15A each (they were already on my 986 equipped with halogens).
Neither of these are required for MOT. TLDR version: If a car has HID lamps and is fitted with washers and / or self-levelling device, they need to work. If your car doesn't have them, they can't be tested (hence they can't be failed).
Discussed this with my MOT tester, and have had no issues getting my 986 with retrofitted litronics through its MOT. It is worth spending £15 or whatever getting the alignment of the lamps checked, however, before you fit them.
If anyone wants to debate this:
https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/4-lamps-reflectors-and-electrical-equipment#section-4-1-4
The above refers to using HID bulbs in [most] reflector (ie halogen) units.
Self-explanatory.
Highlighted relevant section above, however in reality, this does not apply to the 986 due to the age of the vehicle.
Hope this is of help. I compiled a similar post, when I got into an argument with @The return of Marty Wild about this back in Jan, however he then decided to delete his thread (hence my reply) - I was rather miffed by this, as it took some time to compose.
@Araf, am not one to blow my own trumpet, but is there any chance the relevant bits could be stickied somewhere?