I hope this post is not in violation but I got a small run of Custom Stainless O2 housings done for the first gen Probe and MX6 GT. They will GREATLY enhance performance even if you don't change anything else. Plus they are bolt-on.
They are professionally welded and engineered.
I put em in my online store at:
Portmasters.com Online Store Custom Stainless Turbo O2 Housing for Mazda MX6 / Ford Probe GT 2.2L
Note the huge size difference from stock.