A little digging on Xtrac's website you can find their lists of champions - they don't list either F1 championships for Brawn or Mercedes (2009 and 2014-onwards), so we can at least say they don't supply them any more. They do list drivers and constructors for 2010-2013, so they supply(/supplied) Red Bull.
Proud supplier to championship winners in 2009 including:
Dakar Rally - 1st, 2nd, 6th, 7th, 8th, 9th
World Rally Championship - Drivers, Teams & Constructors
HiQ MSA British Touring Car Championship - Drivers, Teams & Constructors
Grand AM Rolex Sports Car Series (DP) - 1st, 2nd, 3rd Drivers, Teams & Constructors
Grand AM Rolex Sports Car Series (GT) - 2nd & 3rd Teams
Sebring 12 Hours – 1st, 3rd, 6th, 7th (Overall)
Sebring 12 Hours LMP1 - 1st & 3rd
Sebring 12 Hours GT1 - 1st, 2nd
Le Mans 24 Hours – 3rd, 4th, 5th, 7th, 8th, 9th, 10th (Overall)
Le Mans 24 Hours LMP1 - 3rd, 4th, 5th, 7th, 8th, 9th
Le Mans 24 Hours LMP2 - 1st, 2nd, 3rd
Le Mans 24 Hours GT1 - 1st, 2nd, 3rd, 4th
Super GT GT300 - Drivers, Teams & Constructors
A1GP 2009 Team Ireland
Indianapolis 500
IRL Championship
ALMS (American Le Mans Series) LM P1 - Drivers, Teams & Constructors
ALMS (American Le Mans Series) LM GT1 - Drivers , Teams & Constructors
FFSA GT Championship - Drivers, Teams & Constructors
LMS (Le Mans Series) LM P1 - Drivers, Teams & Constructors
LMS (Le Mans Series) LM GT 1 - Drivers, Teams & Constructors
AMA Motocross Lites - 2nd, Riders, Teams & Constructors
AMA Supercross Lites – 1st & 2nd (East), 2nd& 3rd (West)
SCCA Speed World Challenge Touring Car Championship -1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th Drivers
SCCA Speed World Challenge Touring Car Championship -1st, 2nd, 3rd Teams & Constructors
SCCA Speed World Challenge GT Championship – 1st Drivers & Teams - 2nd Constructors
Redline Time Attack – Unlimited Front Wheel Drive
Stock Car Copa Nextel Brazil - Drivers, Teams & Constructors
TC2000 Argentina Touring Car - Drivers, Teams & Constructors
Proud supplier to championship winners in 2014 including:
Dakar Rally - 1st, 2nd, 3rd, 5th, 6th, 9th, 10th, 11th, 12th
Daytona 24 Hours (Prototype) - 2nd, 4th, 5th, 7th, 8th, 9th, 10th
Monte Carlo Rally
Sebring 12 Hours - 1st, 4th, 6th, 7th, 8th, 10th
Indianapolis 500
IndyCar Championship
Le Mans 24 Hours - 1st, 2nd, 3rd, 4th, 6th, 7th, 8th, 9th, 10th (Overall)
Le Mans 24 Hours LMP1H - 1st, 2nd, 3rd, 4th, 5th, 6th, 7th
Le Mans 24 Hours LMP1L - 1st, 2nd
Le Mans 24 Hours LMP2 - 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th
Le Mans 24 Hours GTE P – 2nd, 4th
Le Mans 24 Hours GTE A - 1st, 6th
World Rally Championship – Drivers & Constructors
South Africa National Rally Championship
Middle east Rally Championship
Asia-Pacific Rally Championship
MSA British Touring Car Championship - Drivers
MSA British Touring Car Championship - Constructors
TORC Pro-4 Championship
Lucas Oil Off-Road Pro-4 Championship
Proud supplier to championship winners in 2013 including:
Dakar Rally - 1st, 3rd, 4th, 5th
Daytona 24 Hours (Prototype) - 1st, 2nd, 3rd
Sebring 12 Hours LMP1 (ALMS) – 1st, 2nd
Sebring 12 Hours LMPC - 1st - 6th
Sebring 12 Hours GT - 1st, 4th, 5th, 7th, 8th, 9th, 10th
Indianapolis 500
IndyCar Championship
FIA Formula 1 - Drivers & Constructors
Le Mans 24 Hours - 1st, 2nd, 3rd, 4th, 5th, 7th, 8th, 9th
Le Mans 24 Hours LMP1 - 1st, 2nd, 3rd, 4th, 5th
Le Mans 24 Hours LMP2 - 1st, 2nd, 3rd
Le Man 24 Hours GTE A
WEC (World Endurance Championship) LM P1 - Constructors
ALMS Michelin Green X Challenge GT, 1st, 2nd, 3rd
Blancpain Endurance Series
British GT Championship
MSA British Touring Car Championship - Drivers, 1st - 10th
MSA British Touring Car Championship - Teams, 1st, 2nd, 3rd
MSA British Touring Car Championship - Constructors, 1st, 2nd, 3rd
World Touring Car Championship - Drivers, 1st, 2nd, 3rd, 5th, 6th, 7th, 8th , 9th, 10th
Dominican Touring Car Series (DTS)
World Rally Championship – Drivers & Constructors
FIA Cross Country Rally World Cup - Drivers & Constructors