For a sport known for its outspoken, colorful characters, the champions of the two major racing series in the United States let their actions do the talking.

NASCAR champion Jimmie Johnson and IRL champion Sam Hornish are not the most quotable athletes in America. But both displayed an uncanny ability to respond to the challenge and were rewarded with titles.

Johnson represents the "corporate image" of NASCAR. The driver from El Cajon, California who bears a striking resemblance to music star Dave Matthews is usually willing to talk but often speaks as if he was prompted by a sponsor pitchman.

But this is exactly the image NASCAR wants as it continues to move away from its roots as a regional, hell-raising, backwoods sport. NASCAR has homogenized itself to appeal to a diverse mix of economic backgrounds and enjoys tremendous national sponsorship involvement.

However, the tremendous growth the sport enjoyed in the 1990s that extended into the early part of his decade has slowed dramatically. With its highly publicized "Chase for the Championship" in its third year, fans remain skeptical about the 10-race, 10-driver format.

Some of the tracks in "The Chase" had empty seats in the grandstands. Texas Motor Speedway, considered by many the gem of the series because of its modern facility and flair for promotion, had empty seats visible on the backstretch and in the grandstands around the first and fourth turns.

And while the season finale at Homestead - where the series title was up for grabs - was a sellout, TV ratings were off a staggering 20 percent from the previous year.

Criticism in The New York Times and USA Today had NASCAR chairman Brian France backpedaling for an answer to the drop-off in interest. He contended that with the series returning to ABC and ESPN in 2007 and a standardized "Car of Tomorrow" rolling out for a portion of the races next season, that interest should return.

While there was plenty of talk in the garage area about the issues that affect the sport, Johnson's season spoke loudly for his ability as a champion as he finally shed the label of the best driver not to win the title.

Johnson became the first driver to win the sport's two biggest races - the Daytona 500 and the Allstate 400 at the Brickyard and the championship in the same season.

The season began in controversy as crew chief Chad Knaus was ejected from the Daytona 500 when Johnson's Chevrolet Monte Carlo did not pass post-qualifying inspection. That did not stop the driver from leading the final 17 laps to score his first win in NASCAR's biggest race.

Johnson got off to his typical slow start in "The Chase." The low point came at Talladega, where he appeared primed to pass Dale Earnhardt Jr. for the victory in the third turn of the last lap before teammate Brian Vickers ran into the back of his Chevrolet, turning the car into Earnhardt's Chevrolet.

Instead of making a huge gain in the standings, Johnson found himself 156 points out of the lead in eighth place, and the title again appeared to be a dream. But he finished no lower than second over the next five races, including a victory at Martinsville Speedway in October.

That gave Johnson a comfortable 63-point edge over Matt Kenseth entering the final race. A ninth-place finish secured Johnson's first championship in a season where he earned a staggering $15,952,125.

"The first thing that comes to mind is looking at the road that I went down to get to this point in my career," Johnson said. "I think it speaks volumes for NASCAR, how we're evolving as a sport that drivers from all walks of life, all forms of motorsport, can succeed in our sport. With my two-wheel background, off-road buggies and trucks, up through ASA, into Busch, I've been able to make it to this level.

While Johnson was able to celebrate the Nextel Cup, Kevin Harvick's second career Busch Series title was even more impressive. He set a record for largest championship margin of any NASCAR series, beating runner-up Carl Edwards by 824 points.

"They just ran us in the ground," Edwards said. "I was proud to stay within 1,000 points of him."

Harvick had nine victories, just one short of the series record set by Sam Ard in 1983. Add 23 top-five finishes and 32 top-10s in 35 races, and it's about as close to perfection as a NASCAR driver can accomplish.

"The whole year was filled with defining moments because it was such a great year," said Harvick, who also was in the hunt for the Nextel Cup until the final two races. "The first Charlotte race, we made up two laps and finished eighth. That was the moment we felt like we could overcome anything.

In the open-wheel IRL, Hornish became the first driver to win the championship three times. The IndyCar championship was the first for Penske Racing since the team joined the IRL in 2002.

However, the highlight of Hornish's season came in the Indianapolis 500, scoring his first victory in the world's most famous race.

Hornish overcame a botched pit stop where he pulled away with the fuel hose still attached to the car. He was penalized for the mistake, but team owner Roger Penske made the decision to top off Hornish's fuel tank during the "drive through" penalty.

That allowed Hornish all the fuel he needed to make a final charge where the lead changed hands three times in the final five laps. First, it appeared Michael Andretti would finally win his first Indy 500 in his comeback attempt but was passed by 19-year-old son Marco Andretti with three laps to go.

With two laps to go, Hornish tried to pass Marco in the fourth turn but closed too rapidly and had to back off the throttle.

Hornish didn't give up and was able to perfectly time a dive to the inside coming off the fourth turn. He beat the teenager to the checkered flag, marking the first time in the 90-year history of the race that the winning pass was made on the final lap.