Depends on your track racing at...
Did you build it per the book or some ones setup sheet?? I know a lot of people did not like the box setup from the manual, most people in my area started with the Reedy setup since it made it easy and fun to drive and could really push the car.
As for pistons the 2x1.6 fronts and 2x1.7 rear were very popular and made the car feel great. Others ran the stock pistons and liked them. It depends on your driving style and the track. I started with the stock 3 holes to get a baseline race in, then next week switched to the 2 hole ones I made myself from the blanks. The 2holes were a big improvement.