Just saying, I did this on a commuter MTB thinking I'd shed a pound or two and enjoy the hi tech CF rigid fork. Well, though it looked pretty cool, it transferred every detail of uneven pavement, potholes, etc. The ride went from plush to unpleasant. Fortunately, I saved the cooked vintage fork which I re-installed and dumped the hi priced carbon fork on ebay.

If you opt for a rigid, don't dump your susp fork until you're sure you like the outcome.