I have never seen an automobile manufacturer choose to use coolant as an intake manifold heat source. That alone should speak volumes about what factory R&D people think of the idea. Even water-heated automatic chokes were tried for a short time, and promptly abandoned in favor of electric choke heaters because the chokes couldn't be released fast enough to meet federal exhaust emission standards.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!