Chris.
Some have used the ST NVA in the Fox 35. It takes off the top end but gives stronger fuel draw, but if the tank is setup correct the Fox has plenty of fuel draw with the stock diameter NVA. Randy had some PA Fox replacement NVA's that are about the best you can buy. If you use the ST some have opened the venturi one drill size, this seems to work ok but the PA NVA is really the best.
Best, DennisT