If you're interested in picking up one of these cars, but want to know what the differences are, here is a pretty nice BoP test done by iRacing Pro Driver Beau Albert.
The Audi is quick for it's class, the Hyundai is stable, and the Honda is a monster-breaker. The Audi has very few downsides, the Hyundai is a good all-rounder, but the Honda has some work to do...
Now, is this an iRacing thing? Or a Honda thing? The cars that were scanned came from the U.S.-based IMSA Michelin Pilot Challenge, and Hyundai dominated that.
The Elantra finished it's debut season in 2nd and 3rd, only losing to their predecessor, the 2020 Veloster.
In both 2020 and 2021, the Audi R3 LMS was the first non-Hyundai in the championship, finishing the 2020 Season in 4th and 5th, and the 2021 season 5th and 7th, and finished 2nd in the manufacturers championship both years.
Finally Honda only managed 7th in the 2020 standings, with only one car (the iRacing scanned LA Honda World Racing) completing the full season. 2021 wasn't any better as Honda ended the season 8th and 9th in the championship, and LA Honda World Racing finished 15th, only competing in the first 3 rounds of the season.
Over in Europe, things were much better for Honda. In the TCR Europe Touring Car Series, Honda finished the 2021 season in 2nd place, only beat out in the championship by a VW-powered Cupra Leon. The Hyundai Elantra finished in 3rd, and the Audi RS3 LMS took 4th. However, the top-10 consisted of two more Hyundai's (5th/9th) and another Audi (8th) before you got to the 2nd Honda (10th).
What about home soil? Well, Audi took part in the 2021 TCR Asia Series, but that series was dominated by Chinese-owned/Swedish-Made "Lync & Co", and the only other manufacturers were MG, Volkswagen, and CUPRA Leon. So much for home-field advantage.. (To be fair, massive asterisk as COVID really killed any motorsports in the region. The 2021 Asia Le Mans Series, for example, only featured something like four rounds held over two weekends, and that's kind of the tale across all Asian-based motorsports that I can find.)
SO! What does all this tell us? Not really a whole lot. There are so many variables in the real-world, and admittedly I didn't watch these cars turn a single lap this year. From an iRacer's point of view, the video displays that the Audi is the best, but the Hyundai is competitive, and if you enjoy going against the grain, and being the underdog to shove it in people's face, then the Honda is the car for you in this series.
As far as the real world, I don't even know if the Audi was scanned from a team, or if it was scanned directly from the Audi-factory, the Hyundai came from a proven championship caliber team, and the Honda came from a team that, while reasonably consistent in 2020, didn't really put up much of a showing in 2021. How much did that effect iRacing? I'm not sure. Hopefully they had access to data from more Honda teams, either from the teams themselves, or from the Honda Performance Development offices, but who knows.