I went with a PLX.
I wasn't aware that AEM had a NB output, but they do I guess. I'm happy with mine for the most part though.
If you go through the wideband thread in zetec tuning you should find one of my posts with links to virtually all the WBO2 sites, I may have missed the DIY stuff, but if you are in the know you'll already know of them.
Don't "think outside the box".
There is no box.
Do it correct, or do it twice.