I get the choice of black pack for those cars without the S specification satin trim. It's main attraction being the fact it lifts the rear skid plate / valance by deleting the grey, matt unpainted plastic and replaces it with the piano black glossy finish. For me, that's a 'no brainer'.
On the S models, I think it depends upon whether you like the satin accents or not. I do, others don't. My son preferred the black pack but now, three weeks into ownership, he has declared that he really likes the satin finish on the front, lower doors and rear skid plate. So does Mrs A (avoided yet another option pack cost!).
IRR is an interesting colour. It changes significantly depending upon the intensity of the light and the angle of the sun. The contrast when the car is in partial, dappled shade is beautiful. And in sunshine it is stunning. It's less jaw droppingly beautiful on a dull, cloudy day. I think this is even more true of some of the other colours in the palette - particularly DSB.
If the weather is right and my car doesn't spend too long with the dealer because of the rubbing noise on the OS front wheel, I am hoping to spend some time on her so that I can really get the flakes in the IRR paint to pop in the sunlight.
Each to their own.....
Arianne