Think it depends a lot on the individual - lightweight, bio-mechanically efficient runners, probably not too important what they wear.
For the rest of us - I've gone through lots of makes, currently wear Addidas (Trail shoes) Mizuno (Wave riders as race shoe) and some other Mizuno for Tri's and a Decathlon own make for training - all good.
In the past have bought cheap Etonic and had to throw out as they caused intense Knee/hip pain which I'd never suffered from before or since,and some New Balance that blistered me, but these may just have been aberrations, difficult to say.
So, as always with running shoe advice, each to his own, we're all so different!
? is not really relevant to runners, both TG and TM are for blokes/blokess's from the pub who want a laugh and something to boast about when back in the pub!
If you want to do something tough try an Ironman, or an Ultra.
And yes, I have done TG, Hellrunner, Grim etc.etc. None are that tough, any Marathon is harder. (assuming you don't break a leg, all I got was 5 stitches in my shin after a water hazard that contained real hazards)
yup, bit hilly, as Chunky says, but what goes up etc. and none of them is a walker, can all be shuffled up with not much of a problem (did a 1:47 last year as an indicator of my standard, i.e. old and slow!)
Initial reaction to your post - you'll be swept if there's a sweeper. Looking into your event that's not going to happen; you can take the full 24 hours if you like!
I did the Spitfire Scramble recently, a 24 hour event, and some "runners" did a 100+ miles, so your target is definitely doable.
Although we're all different, and you don't say what level of runner you were 2 years ago, I very much doubt you will be able to even jog 100K and so will echo Millsy's advice - Walk, jog a bit, but you main problems will be maintaining energy and mental stamina - so practice a few long "runs"
I'm not a fan of training plans, stick to foods/drinks that won't upset you stomach, make sure you take plenty of rest stops, and, if at all possible, have a back up crew to meet you at certain points with your food/drink/encouragment - it makes a world of difference on an ultra if you know someones waiting 5miles ahead!
and just to throw another spanner in the sea of logic... following up from literatin's point re fast older runners.
Surely if an over 60 wins a race outright, not as impossible a hypothesis as it might seem, (check out peter butler on powerof10, he ran a 77HM this year!), then...
Should he/she not be given all the prizes, 1st over all, 1st senior and 1st in every age group up to the 70, if there is one? After all, by Mr puffys's logic, if all the younger runners were beaten by an over 60 they don't deserve a prize!
All of which brings me back to my original premise, isn't one runner, one prize a "fairer" system?