When NASCAR switched from a rear wing to a spoiler on its Sprint Cup car seven weeks ago, the fear in the garage was that Jimmie Johnson and his team would adjust to the change more quickly than everyone else and simply pull further away from the competition.
There were plenty of reasons to justify those fears.
Johnson, of course, is the four-time defending champion and he and his Hendrick Motorsports team have basically dominated the sport the past four years.
He also drives for the most dominant organization in the sport. Hendrick teams have won nine of the past 15 championships and swept the top three spots in the standings last year.
Johnson then began his quest for a fifth straight title by getting off to the best start of his career, winning three of the first five races this season.
If the switch from the wing to the spoiler didn't faze them, then Johnson and his team were likely to just widen the gap on the competition and cruise to another spectacular season.
But surprisingly, it hasn't happened - not yet.
Gibbs and RCR have won the past four races, with Denny Hamlin winning twice and Gibbs teammate Kyle Busch once. RCR's Kevin Harvick has the other win and is expanding his lead over Johnson in the points standings.
The spoiler made its debut March 29 at Martinsville Speedway, but had very little impact on the flat, half-mile track, where aerodynamics don't mean much.
But in the past five races - at Phoenix, Texas, Talladega, Richmond and Darlington - the spoiler has made an impact, and it's the Gibbs and RCR teams that seem to have it figured out.
The best average finishes over the past five races belong to Busch (5.6) and Harvick (6.0). Both have won races and Harvick has padded his points lead while Busch has climbed from 12th to third in points.
Hamlin, meanwhile, has won three of the past six races and has climbed from 19th to sixth in points.
RCR's Jeff Burton has also been running strong with the new spoiler. He has led each of the past four races and was in position to win the last three.
Earnhardt Ganassi Racing has also picked up steam in recent weeks, with Juan Pablo Montoya scoring three straight top-10 finishes and Jamie McMurray winning the pole and finishing second at Darlington.
Hendrick teams, meanwhile, have struggled the past five weeks - with the exception of Gordon, who has run with the Gibbs and RCR teams and, like Burton, has seen three dominant performances come up short.
"It's made a significant change in the sport," says Kurt Busch, who also seems to have adjusted well, with three top-10 finishes in the past four races.
"Some teams have adapted to it better than others, and there could be different drivers within the same organization that have done better or worse with it.
"Jeff Gordon has really flourished with the new spoiler, where Mark Martin has struggled a little bit. So I find it interesting on how it's balancing the car different, whether it's front downforce, rear downforce, driving styles, and so we're starting to see what the spoiler's change is doing."
Johnson started strong with the new spoiler, finishing third at Phoenix and second at Texas before hitting a skid. He has finished 31st, 10th and 36th in his last three races.
He was involved in wrecks at both Talladega and Darlington, but was clearly struggling in both races before finding trouble. His mini-slump has raised questions about whether Gibbs and RCR have finally caught up to the Hendrick juggernaut.
Martin has also been off his game. He had two wins at this point last season, but has a bit off this season, particularly in the past two races at Richmond and Darlington, tracks where he has been good in the past.
Martin admits that his team has struggled a bit adapting to the latest changes.
"I don't think about [the spoiler], but that is one thing that has changed," he said last week at Darlington. "We saw signs of being off on our performance before we switched - let's say at Atlanta with the wing. We have seen more since we switched; although, we also saw our two best performances.
"We've had some really good runs and we've been off a few weeks, and part of that is just the competition and part of that is us trying to up our game. It may be the difference in the spoiler ... That is the one thing that has changed."
Johnson says all of Hendrick has been trying to adjust, and experimenting for later in the season.
"Here lately, we've been working hard to find new speed and some new stuff to make the No. 48 car strong when it is the right time of the year. I think we are getting close," Johnson said at Darlington.
"I know Jeff and those guys have been working in some areas and it has been working well for them. Mark has been experimenting and hasn't really found what he needs.
"So we are all kind of massaging our packages and I hope that we get what we need out of the No. 48 car soon so we can get back to Victory Lane."
The team that appears to be struggling most with the new spoiler is Roush Fenway Racing, which expected its veteran drivers to excel with the new package.
Instead, Greg Biffle and Matt Kenseth have fallen off while Carl Edwards has maintained his subpar performance.
Biffle got off to a strong start, but has an average finish of 18.6 in the past five races, including three finishes of 22nd. He has fallen from third to seventh in points.
Kenseth was second in points before the switch, but has finished 20th, 28th, 13th and 13th in his past four races to fall to fifth in the standings.
Does the new spoiler have the Hendrick and Roush teams baffled, or are they just experimenting and saving up for a strong run going into the Chase for the Sprint Cup?
Or is the new spoiler indeed a true spoiler, leveling the playing field and closing the gap between Hendrick and NASCAR's other elite teams?
Has it given Gibbs, RCR, Earnhardt Ganassi and others a chance to win races and make a serious challenge for the championship?
It certainly looks that way - for now.