the mechanic was talking about the spark plug wires coming off out of ur valve cover and to the distributor, u can replace them with the oem wires or for a few extra bucks get an after market set. dont expect great hp gains or nething like that, it will allow ur electrical system to work a little easier but dont believe anyone at a parts store telling u ur gonna see a gain of 5 hp cuz u wont, u'll just restore ur engine to its factory performance, most oem wires run 10mm wires while most aftermarket wires will be a 7 or 8 mm wire, id say compare prices and decide for urself, for a few extra bucks id say go for it, for 20-30+ id say screw it and do oem. as for spark plugs use the ones recommended for ur car, (assuming ur not doing any extreme aftermarket parts like turbos or nitrous)