Speed & Off road, all vehicles will tail, however, because of their length, longer vehicles tail slower as compared to short wheel based vehicles thus giving the driver a little more time to react thereby a better chance of controlling it. Similarly, the chances of longer wheel based vehicles of experiencing a rear wheelie is lesser than a short wheel based. Disadvantage of longer wheel base is the extra weight that it has to carry.
Trick is to have the best of both worlds, that is why the current generation of rally raid vehicles are stretched 3 door versions.
I dont think Nadir's LC has any speed advantage over Evo, he may have a little better torque in soft sand because of being on diesel but Evo has very strong 2nd and 3rd gear. In fact it touches 160 in the 3rd, which makes Evo, if not stronger, atleast at par.
In Cholistan 2010, TDCP had requested Motorway Police to manage the start and finish lines. They brought their speed guns and informed public the speeds at which each vehicle crossed the finish line. The fastest there was Ronnie, who crossed at 170, Nadir was at 160. Ahsan's Nissan VTC crossed at 164.
So, while admitting that Nadir's LC is very well prepared, its not his LC that consistently wins him titles, its mainly his driving.