My stock 97 when I first had it, saw upwards of 7*+ of KR from the factory. Seeing you only have 2-3* after a PLOG/DP combo, seems not to out of the ordinary. Add a little fuel and see if that cures the issue. I'd also replace the plugs as well. Since you're on a stock pulley, run AL606's since thats stock heat range. You want the hottest spark possible. When you drop pulley sizes, then swap to AL104 or even AL605's.