Personally I never used a heated (water) intake manifold.
I never needed it in SoCal. Got great gas mileage ,my manifolds warmed up quickly,it's right over the headers which are really hot,so basically & never wanted my manifold that hot anyways.
I would rather have my intake cooler,it would always just get heat soaked from the headers.
My car would run better w/a cooler intake.
Two cents thrown. :-)
MBHD
