I'll take this one @suhaibkiani!
Only if you insist on using a puny 8" 2L or 3L clutch. The 1UZ puts out at least 250 lbs/ft of torque and it NEEDS a 10" or bigger clutch, like a 1KD, 1KZ, or B series unit. The stock bell housing needs slight modification to accept one of these larger clutches but it's very easily doable. If you use an adapter plate between the engine and bell housing then no bell housing modification is required.
How well does a 10" clutch hold up? Just fine as my 1KD clutch would tell you if it could speak. Its 780 KG clamp load is sufficient to prevent any slippage even with the 2.73:1 diff ratio I am using which is EXTREMELY hard on the clutch to begin with. I run this vehicle hard regularly AND I use it for towing as well. but still no issues. Why? Because I never ABUSE the clutch with half pedal burnouts. Most clutches die an early death thanks to inexperienced operators letting the pedal out only halfway while gunning the engine needlessly.
I've never heard of any issues with the 1UZ's own auto trans, which can be mated to a Toyota transfer case, if you want, for four wheel drive.
You haven't looked in the right places. My 1UZ CJ7 has been my daily driver and recreational off road vehicle for the last two years. I've had zero problems with the engine conversion. Fully satisfied 1UZ user here.
Nope. There is nothing wrong with using an adapter plate to mount the transmission, provided it is properly centered. This is such a common mod, one should have no issues with it. As for the choice of transmission, a R150F or R151F manual transmission out of a 70 series is a perfect swap. Not only are R series transmissions incredibly strong, but the ratios also match perfectly and you won't have to take out a second mortgage on your house like you would with the 100 series drivetrain. Throw in any Toyota axles with 3.7:1 ratio diffs and you've got yourself a winner.
The Prado's autobox works flawlessly with the 1UZ ECU. The engine itself is happiest with 3.7:1 ratio diffs on 31" tires or 4.1:1 with 33" tires. You need to avoid the incompetent hacks who are telling you otherwise and showing you poorly engineered examples of 1UZ swaps