One of Spa's unique features is that the class structure is based solely on driver grading, with all cars conforming to GT3 regulations. There will be five categories at the 75th edition – Pro, Gold Cup, Silver Cup, Bronze Cup and Pro-Am – each with its own rules and requirements.
First, it's worth mentioning a few regs that are applicable to all classes. Over the full duration of the race, no driver can spend more than 11 hours in the car, down from 14 at previous editions.
A minimum driving time of two hours has also been instituted when no other requirement is listed. The maximum continuous driving time is three hours and 15 minutes, after which there is a mandatory one-hour rest.
PRO: In terms of performance, this is the premier category. Each crew is restricted to three drivers, but there are no further limitations. Indeed, as the name suggests, a Pro line-up usually consists of professional drivers, many of whom are contracted to a manufacturer.
It is worth noting that this not a 'cup': for example, if a Gold or Silver crew secures the overall victory, there will be no separate 'Pro winner'. That is yet to be put to the test, however, as Pro crews have filled the overall podium every year since the current class structure was introduced in 2011.
GOLD CUP: Though the name was used last year, this effectively a new category. The maximum line-up is Gold-Gold-Gold-Silver, though the majority of the field will run with Gold-Gold-Silver trio.
In either case, the Silver driver must complete a minimum of four hours over the course of the race. In terms of performance, we can expect the leading Gold Cup crews to break into Super Pole and perhaps even challenge for an overall top-10 finish in the race.
SILVER CUP: First introduced to the 24 Hours in 2018, the Silver Cup remains unchanged for 2023. Each crew consists of up to four Silver-graded drivers, with no extra limits placed on driving time.
The fourth driver is optional, with three of this year's field electing to maintain their full-season Fanatec GT Europe Endurance Cup crews. This tactic was used to good effect last year, when Team WRT triumphed with its established trio of Neubauer/Goethe/Simmenauer.
BRONZE CUP: This will be the biggest class at this year's race. While the name has been used before, it is effectively last year's Gold Cup category, with a maximum driver line-up of Platinum-Silver-Silver-Bronze. The Bronze must contribute a minimum of four hours during the race, which must include one hour within the first six. The Pro can contribute a maximum of eight hours.
The reigning class winners are the Iron Dames, who return with an unchanged driver line-up. The Bronze Cup has also attracted several powerhouse squads, including six-time Pro-Am winner AF Corse, and recent overall winners Team WRT and Walkenhorst Motorsport.
PRO-AM CUP: Last but by no means least, Pro-Am. Indeed, this is a mainstay of the 24 Hours, having been part of each edition since GT3 rules were introduced in 2011. The maximum line-up is two Platinum and two Bronze-graded drivers.
In terms of driving time, a Bronze must be behind the wheel for a minimum of eight hours during the race, and for at least one hour during each six-hour period. This time can be shared between two the Bronze drivers.