Well 2.8 B5's are plentiful and cheap in my area, I'm considering buying one and swapping a DBW 1.8 in it so everything forward of the firewall would be swapped.
I swapped a DBW 1.8t into my '99.5 2.8 and you definitely don't need to swap over the dash harness. Apart from some connector re-pinning you need to make a small harness for the pedal and cruise control, and you need to tap into a switched 12v source (I used one from the ABS circuit because that's how it was done in '01). You can also keep the stock cluster, but you'll have to make a couple of small changes to your engine harness (switch some pins, run a wire or two). The most difficult part of the swap for me was doing all the research and swapping the pedal cluster.
This is what I have documented:
https://dl.dropboxusercontent.com/u/63667361/AWM%20swap.zip I can't guarantee everything's 100% correct and nothing's missing, but I'll be able to answer any questions you have.