Firstly the S1:
Check out the interior photos of the clocks to see S1 moniker, and check out the underside - no propshaft indicating it MAY not have Haldex on S1.
2: The (I'm not so sure) RS1
In these photos you can see the haldex propshaft running down the centre of the car (underside photo). The RS just doen't look RS enough for me, and I'm thinking they may be doing a compare and contrast to see whether the S1 really benefits from Haldex, or whether it makes more economic sense (given likely costs) to stick with 2wd and still use and S badge (at which point we'll all know the badges are truly for marketing purposes in the 2010's!). Make your own minds up, but I think this can't be an RS, irrespective of the part number on the ARB!
If it comes with a 2.0T and Haldex it's @r$e is mine!