Wouldn’t touch par if they gave it to me.
You need to ask how much power you’re looking to make and then add about 50% to it because that’s what you’ll end up making
The factory box says no more at about 350kw or so, the upgraded synchro boxes won’t handle much over 500kw for long and at that point you’re looking at an auto or dog engagement manual,
once you’ve gone dog engagement you may as well go sequential, they cost a little bit more but it’s worth it
also while you’re at it you should upgrade the transfer case with 10 friction plates