SELECT "Fastest Lap" FROM table_20946 WHERE "Winning Team" = 'Team Impul' AND "Circuit" = 'Twin Ring Motegi'
Who had the fastest lap in the race won by Team Impul at the Twin Ring Motegi circuit?
CREATE TABLE table_20946 (
    "Round" real,
    "Circuit" text,
    "Date" text,
    "Pole Position" text,
    "Fastest Lap" text,
    "Winning Driver" text,
    "Winning Team" text
)