intake manifold heat riser

What has been said and more:
On a street driven car..
Warming manifold quickly makes car more drivable quickly.
Makes fuel efficiency better during initial 15 - 30 minutes.
Prevents raw fuel washing oil from cylinders so prevents accelerated engine failure.
ALSO, prevents raw fuel from polluting your oil and ruining it, so prevents accelerating engine failure.
Reduces need for massive accelerator booster mods needed or need to compensate for increased manifold wetting delay and effect.