I'm retiring my 7 year old Genesis Silver C grill to the pool area for late night swims and snacks for the boys .I want a Summit , not sure if I should go with the 650 or 670 ? Can the area for the sear center be used as a reguklar grill area as well or is in a different kind of grate only for searing , so is the square inches of primary cooking area the same in a 650 and a 670 ? What holds up better to the environment the Porcelain hood or the stainless .I read online that the stainless gets discolored from the heat ? but the E series does not get as hot as the S series ?Sorry for all the questions just before an investment like this I like to research with the experts.THANKS