Unlike the requirements for the preceding Group A cars, manufacturers were no longer required to build "homologation specials" in order to meet approval. The base model did not need to have all the characteristics of the WRC car, as evidenced from cars such the Peugeot 206, 307, Citroën Xsara and Škoda Fabia, which during this period had no road car variant with a turbocharged petrol engine or four wheel drive. One of the requirements was a minimum length of 4000 mm; the standard Peugeot 206 had an overall length of 3835 mm and Peugeot had to produce at least 2500 units featuring extended bumpers to comply with the required dimensions.[2]

Analysts spend thousands of hours trying to mathematically determine what will trigger the next rally and how long it will last. Technical analysis is especially prevalent in this effort, although less sophisticated indicators such as hemline fashions or the NFL division of the latest Super Bowl winner also provide fodder for such predictions. This in turn can sometimes lead to speculation that a rally is just around the corner, which can then become a self-fulfilling prophecy.
McRae rejoined Prodrive for the 2004 24 Hours of Le Mans where he took third place in the GTS class, and ninth position overall in a Ferrari 550-GTS Maranello partnering Darren Turner and Rickard Rydell. Fellow countryman, and Le Mans winner Allan McNish commented that "Colin has adapted far better than people expected" to endurance sportscar racing.[20]
The gear changes must be made with a mechanical system, so the paddle shifters were not allowed. However the system was re-allowed in 2015. There was no center differential (earlier it used to be 3 differentials, with a center/3rd differential included), but the new regulation allows only front and rear axle differential (eliminating the center differential to reduce cost)[citation needed], and they must be mechanical, without electronic control or hydraulic or viscous systems (from 2006 to 2010 the center differential and previously all three could be active[7]). Minimum weight is 1200 kg empty and 1350 kg with driver and co-driver (in both cases with only one spare wheel).[8]
Rallying is a very popular sport at the "grass roots" of motorsport—that is, motor clubs. Individuals interested in becoming involved in rallying are encouraged to join their local automotive clubs. Club rallies (e.g. road rallies or regularity rallies) are usually run on public roads with an emphasis on navigation and teamwork. These skills are important fundamentals required for anyone who wishes to progress to higher-level events. (See Categories of rallies.) Short special stage practice events on public roads are in some countries organized by the local clubs, with a permission of the local police, the community normally using the road, and the road authority. The public road is closed during these by the organisers or the police.
A typical rally course consists of a sequence of relatively short (up to about 50 km (31 mi)), timed "special stages" where the actual competition takes place, and untimed "transport stages" where the rally cars must be driven under their own power to the next competitive stage within a generous time limit. Rally cars are thus unlike virtually any other top-line racing cars in that they retain the ability to run at normal driving speeds, and indeed are registered for street travel. Some events contain "super special stages" where two competing cars set off on two parallel tracks (often small enough to fit in a football stadium), giving the illusion they are circuit racing head to head. Run over a day, a weekend, or more, the winner of the event has the lowest combined special and super special stage times. Given the short distances of super special stages compared to the regular special stages and consequent near-identical times for the frontrunning cars, it is very rare for these spectator-oriented stages to decide rally results, though it is a well-known axiom that a team cannot win the rally at the super special, but they can certainly lose it.

Rising investor confidence also indicates a rally, and it is perhaps more powerful than any economic indicator because when investors believe something is going to happen (a rally, for example), they tend to take action (purchasing shares in order to profit from expected price increases) that actually turn expectations into reality. Although it is an objective concept, investor sentiment shows through in mathematical measurements such as the put/call ratio, the advance/decline line, IPO activity, and the amount of outstanding margin debt.