From what little Steve has written on this board, I think he does want to beat Kurt.
Having said that, I don't think Steve needed UMCA. The technology is in existence for him to prove his achievement for all to see, with no possible doubt about its veracity. If Guinness thinks it can adjudicate what it does and does not recognise as a record on grounds of perceived safety, then they are just diminishing themselves. Do they not recognise Alan Hinkes' record as the first Briton to conquer all 14 8000' peaks? I would wager that there is a lot more risk in that than going for a 100000 mile bike ride. The internet, via Strava and this forum, will demonstrate the record.
Getting the UMCA involved has, however, brought Tarzan into the fray and that has added a lot of interest. Steve v Tommy was one thing, but Steve v Tommy with an intruder trying to spoil the party has added a great deal of extra excitement to the whole affair.
Will both, or either, finish? It's too early to say, but Tomsk and I were discussing the issue at the Essex Christmas do. We both felt that the only thing that would stop Steve would be injury or illness. On the basis that both Steve and Kurt are equally likely to sustain a ride-threatening injury, I think external factors are much more likely to handicap Kurt than Steve. Steve has completely cleared his life from everything but this ride for the whole of 2015. Kurt clearly hasn't.
Having said all that, if they both complete the year without injury or other interruption, on balance I would expect Kurt to do more miles than Steve. They will both beat Tommy, though, and by at least 10000 miles.