@ Fouad, I may be wrong here, but most likely the tyres you are talking about are proper sand tyres and if they are, they can do wonders in desert sands. Though they are not for racing, because lateral handling is not that great.
I have only driven Suhaib's UZi some time ago very briefly on road, so can't say how it handles now, but for me higher tyres mean less lateral stability, maybe the increased width gives the reassurance.
You described high speed chases in Baluchistan in wide open spaces and mostly straight line runs. Well, Jhal was mostly 10-20 feet wide track, which seems a lot narrowerer at high speeds. And usually off the track means a lot lot more bumps / small ditches and strong possibility of roll over.
My NPP is almost a semi-clone of your FZJ79, though its a bit more car like to drive in comparison (have driven HZJ79 both 2005 and 2008 model, briefly). If you are interested in trying out your Daala (I call mine that) in cholistan, you will need to shed awful lot of weight-off for it to be competitive. Just taking off the rear bed improved our timing by nearly 14 minutes at Jhal! For me, next time round the front steel bumper needs to come off and engine hood needs to be replaced with light fibre glass cover! Some quaters even suggested getting front mudguards replaced with fibreglass molds!
Your engine querry, 1FZ vs 2UZ, don't! The 2UZ you will get here is older specs, and thats only 230-235bhp, and 410nm torque. So yes its more powerful, but just a bit more (1FZ = 224hp 387nm). If you get hold of newer 2UZ (vvti version) came in 2006 onwards model, thats 265hp 435nm, that I would recommend you to go for. Better yet find a 1UR (340hp, 460nm). Having said that electronics in these monsters are beyond our local ustaads and hence reliability sword hangs over constantly!
PS; Yes we will be there!