Does the downdraft work well for you? Most people that I know who have them say they're useless. I noticed Candace Olsen likes the Thermador retractable downdraft, and its height probably makes it somewhat more effective than the counter-height Jenn-Air, but for the cost of it plus the blower it requires you could probably install ductwork and a real vent hood!

The only reason I don't like the Jenn air downdraft, is, it pulls the flame when the blower is on. Had one a long time ago.

In the house we are presently in (we are building), we have the Jenn air 30" gas range, not the downdraft, and we have a blower inserted above and it works great! Looks great!