How should a race jacket fit compared to my normal ski jacket?

A race jacket should fit like a second skin with no excess fabric anywhere. When standing upright, it may feel slightly tight across the chest and shoulders—this is correct. In a skiing tuck position, the jacket should move with you without pulling or restricting breathing. The sleeves should reach your wrists with arms extended forward (ski pole position), and the hem should cover your waist without riding up in the tuck. If you can comfortably zip it up and walk around the lodge without feeling constrained, it's probably too loose for racing.