From Reddit:
"GT3 does BoP much more heavily, making a Bentley able to compete with a Ferrari. You could also say GTE is more finely developed than GT3.''
From me:
that says all.............................
i think they tried to organize a championship between all car manufacturers and BOP was the only way for cars to be competitive
Bro.... let me clarify that for you (you could do it yourself by googling about how GT3 works)
GT3 class basically does not have rules, they have a performance target. Manufacturers give their cars to SRO and the organization test driver go in their track and start taking lap times, they only slow down cars to fit the rest of the grid, they limit gear ratios according to the engine power and torque curves, then balance with weight, all setups are also limited by their range to fit the different tracks.
In the past a Corvette would blow away everyone at a track like Monza or cars with better torque would dominate a low speed track, etc. They then created 3 levels of BoP that they use depending if the track is high speed, low speed, etc. This is an attempt to balance the cars more, but fully balanced grid is impossible mostly due to weight distribution.
They'll balance fuel tank size and refuel times so all cars run about 65 minutes also even if one car use more fuel per lap than another.
If the car is slower SRO return the car to the manufacturer and it's up to them to either improve the car or homologate it anyway. Happened to the Lexus GT3, the car was slow then Toyota decided to delay the homologation for a year to improve it.
That's why GT3 works, you dont need to spend too much to develop the car, as long as it fits the performance target and make good use of tires it's fine to go.
GTE class on the other hand has a proper rule book (+ BoP, which can be seen as stupid since you already got a proper rule book). Manufacturers can build their street cars with the GTE book in mind, that's what Chevy did with the C7, the car was made to fit these rules from scratch, according to their CEO.
To say that one is more developed than the other is weird, both are very well developed now, the GTE just have more downforce and some more power.
Other series should actually follow this model tho. Indycar could do that, homologating engines for 3~5 years cut costs big time and we could see a second chassis builders then if they did it