We’ve been covering the ongoing decisions, commitments and defections in sports car racing related to the new Le Mans Hypercar and LMDh prototype categories for a while now. And the news has been largely great: a number of manufacturers are developing cars to one spec or the other, and the WEC’s acceptance of IMSA’s LMDh formula means that whether a team builds a prototype to primarily race in North America or the rest of the world, it can compete for the overall win at the 24 Hours of Le Mans. Fans have been waiting a long time for such a scenario; hell, the vast majority of us probably never expected to see the day.

Today, there’s yet more good news to report. IMSA is returning the WEC’s favor, such that . In simplistic terms, this decision completely breaks down the barriers between the two series. Whether you’re Ferrari or Toyota building LMH cars, or BMW or Acura building LMDh ones, you can run your cars in either championship, and therefore in most of the world’s greatest endurance races.

While there’s definitely been an air of optimism surrounding the future of the discipline lately, the prospect of Hypercars gaining entry into IMSA wasn’t a sure thing. It was clearly an objective both sides seemed interested in working toward, but IMSA was in a position of relative power because the LMDh class is a little more healthily stacked than the Hypercar side of things. In other words, WEC needed LMDh entries more than IMSA needed Hypercars.

It was also anticipated that the IMSA would allow LMDh cars a year or two of Hypercar-free competition before even broaching the subject, as reported. But with today’s announcement, there will be no ramp up to full convergence of the two classes: Hypercars will be permitted entry into IMSA from the very first race on the 2023 calendar, the Rolex 24 At Daytona. 2023 is the same year LMDh cars are expected to debut.

It probably won’t be completely smooth sailing. Le Mans Hypercars and LMDh cars are quite different. The former allows for more flexibility at a much greater expense to constructors, whereas the latter involves a number of spec components (or, choices between spec components, as with LMDh’s four chassis suppliers) designed to encourage involvement and keep things relatively economical for factory teams and privateers alike.

The vast differences between the two categories means that the sacred Balance of Performance — the efforts to engineer performance parity between cars in both classes — may be tough to achieve and will require some ongoing tuning. We already got a taste of that earlier this year at the 6 Hours of Spa-Francorchamps, where Toyota’s GR010 — the first Hypercar on the grid — was against its more conventional LMP1 opponents in early practice running (though it ultimately won the race).

LMP1 is an outgoing ruleset, but the principle remains the same between Hypercar and LMDh. It’s not an easy feat to make two different types of racecars to be about equally quick, especially without manufacturers on one side or the other feeling like they’re getting the short end of the stick.

But that’s a concern for another day. Right now, there’s so much to look forward to. Once 2023 rolls around, we’re looking at a pool of prototypes from Toyota, Ferrari, Peugeot, BMW, Porsche, Audi and Acura, as well as lesser-known names like Scuderia Cameron Glickenhaus and ByKolles. McLaren, Cadillac, Lamborghini, Hyundai and even Lexus (yes, we could have Toyota and Lexus entering endurance races on different sides of the pond) have all been linked to potential LMDh programs as well. And they’ll all be eligible for the same races!