I have no experience with the complete Ansa catback system, only the
bolt-on muffler. I had an Ansa for a few years. Slight surface rusting
is common around the logo stamped into the chrome tip, but it's under
the bumper and isn't easily noticed. The sound was deep and mellow, a
little louder than stock.

I got bored with it--not loud enough--and replaced it with FM Duals. I
sold the Ansa to a guy who needed a muffler badly.

For a used OEM catback, check the various miata.net sponsor vendors.
Many of them save OEM take-offs from customer cars. You might score one
for little more than the cost of shipping.

I've had the Borla on my '95 R for several years, and love it. Simple, direct
cat-back replacement, just enough of a growl to add a bit of character. A
perfect Italian (think Alfa) tone.

-- Larry