This is interesting.
The only reason I have not swapped the pump yet is because I drive with a wideband. Now, I know the risks, so you don't need to remind me, but that is just how it has been.
That said, my b13 is a 91, with over 23k on the clock. I highly doubt it is the stock pump. If it is, then I am lucky.
My pump has been holding power and proper afr fine up to 8k, however I am only making 173whp. Go figure.
Dudeman