Multi-electrode plugs only give the spark more possible paths to take. Electricity will always take the path of lowest resistance.

Properly gapped copper plugs (I use Autolites myself) should prove to be more than adequate, even with DIS. They'll probably wear a little faster than double platinums will, but copper plugs should provide comperable performance.

 

I own a 8 plug 4 banger, it does help with the emission, but also gives your more towing and hauling power, i just hauled 2 54 chevys and a 65 chevy with it, did just fine on take offs going down the road, it also improves your gas milage from the typical 18-19 miles to the gallon to about 20-25 miles to the gallon pending city or highway use, i primarily drive highways miles with mine and avg 24.5 to the gallon, all togther this is a better motor the just the straight 4 plug 4 cylinders.

 

I run premium gas in my 1989 ranger and I get about 29-30 mpg hwy and about 25-26 city plus lotsof hill's and mountains were I live.