The durability concearns seem to be a handful of bearing failures.
Other than that.. Their converters stall speed seems to be on the money out of the box.
As for the 3200-3400, building converters is not an exact science. That is the approximate stall you will see at no boost.
Now, on the brake all bets are off.
Brian
PS. do not stay on the brake for a long duration of time. Good luck