Dual tailpipes for 2000 4dr?

Has anyone installed dual tailpipes on a 4dr with spare underneath?

No, but have seen it out there. I personally think that a catback (single) is better. But, I know that the look of two is nice.

Go to a custom exhaust shop and get a price. I wouldn't attempt to do it myself because before buying a catback I did just that -- and melted a quarter of my bumper off! Good luck!