The site is abuzz as subcontractors hurry to complete their in-wall work before the insulation truck arrives. Tom Silva gives a tour of the wires, pipes, conduits and ducts, while Paul Somerson, editor-in-chief of PC Computing magazine, makes recommendations about the proper wiring, placement and configuration of the house's computer system. Kitchen designer Phil Mossgraber and homeowner Sandra Silva are down to the final decisions in the kitchen - natural fir cabinets, linoleum floor, counters of a material called kirkstone and they debate the merits of two different island designs. The sprinkler system is roughed in, and sprinkler specialist Jack Viola shows our host where the water comes in and (hopefully never) comes out. Media systems designer shows us his plans for outfitting the living room with a surround-sound television package; it includes the rather unorthodox replacement placement of a plasma-screen TV in the wall over the mantle. Finally, landscape designer Stephannie Hub