@ Sarmad, firstly thnx for the appreciation.
Your questions have no clear answers, average speed, well the fastest I hit was 147-8kmph, I am told the front runners were easily hitting 170+. Track had lots of straights (streteches of 25km+) and than narrow twisty bit and finally very soft slow sand almost crawler bends near many check posts. When one says straight, it just means straight ahead, i.e no left and right, but its constant up and down, doesn't feel bad at 90-100, at 130-140 it was my LC all over the track with stock suspension, requiring constant and vigilant corrections through out. And you can well imagine 160-170 would be a different ball game.
No official final time sheet still available to me, very poor show by TDCP in this regards, no one knows anything in their Pindi, Multan, Lahore or Bahwalpur offices. I have requested Qasim Saidhi to pass details when he gets it. So true speed average would become clear than.
However word of mouth was that Nadir magsi did the 226km track in 2hr 21 minutes, Ronnie Patel was a minute or two behind time wise. That makes it 226km in 141minutes = 96kmph.
I don't know my exact full time, but do know my first half time, which was 110km in approx 87minutes. Forgot to stop the stopwatch at end of rally in excitement of finishing :-). Anyway that works out around 75kmph, which I think is pretty good. Afterall we had never planned for any kind of positions. The good old dialogue would fit here nicely, " meray chotay chotay bachay hain" so had to play it real safe, especially as we had no experinece and we were clever enough not to even bother with a recce, which every one will tell you is a must!
We did the rally in true professional CRUISING style, we kept the AC on part of the way, it gets bloo... hot in the helmet with closed windows! than we had Abida Parveen, Reshma and Anup jalota Ghazals playing in the back ground, and later on we had a full on kareoke session as well !!! 
Fishak was busy making vdos during the run.
Finally the tyres, well, most high end vehicles had BF Goodrich all terrain, they must know something. Mine were standard road tyres in stock size, Michelin 275/70 R 16 on original 8 " rims. the tyres were H rated so safe theoratically till 210kmph. Most mud, snow and sand tyres come in Q or R rating, i think thats 160-170kmph, I would be too uncomfortable going at 140+ in those with such little margin, given the amount of resistance the sand generates consiquently the heat production and chances of high speed blow-out! Anyway the H rated tyre gave me an option of very briefly flirting with top speed of 190kmph on the way back at M2.
Theoratically a good sand tyre would give you decent help. But bottom line is you need plenty horses under the bonnet, extremely strong suspension to take the pounding and finally generously sized titanium oval/ round things (somebody described as Stainless Steel Kahunas) on your body to actually push the damn thing to the limit !!
