With the fuel pump and turbo upgrade i reckon my 5th is stronger. Ive changed diff ratuos too so the rev range under load is in our fa our now @AB lagging at 2000 at 100kmh is average and causes over heating and maybe stress on the 5th.
I towed from the Murray with the camper in 5th on cruise at 115 all the way homw. Up hill ans down hill, it didnt feel a thing.