The other GTP manufacturers are reeling in Aston Martin a little bit: BoP breaks for almost every manufacturer ahead of the upcoming round at Laguna Seca Raceway in Monterey.
Following the tight corners of Long Beach, where heavier weight might not be as much of a problem, the IMSA WeatherTech Sportscar Championship heads to the hilly Laguna Seca Raceway as its next destination with a slightly tweaked Balance of Performance (BoP).
Every manufacturer except Aston Martin, who is already at the best possible limit, will receive a more advantageous power-to-weight ratio compared to the Streets of Long Beach.
In particular, the Porsche 963 lightens from its mandated 1,100 kilogram weight but remains the heaviest GTP car at 1,084 kilograms and 480 kilowatts of power below 190 kph.
Below 190 kph: Porsche still on a different level
Crunching the numbers, the following picture emerges when calculating power-to-weight ratio below 190 kilometers per hour:
- Aston Martin Valkyrie - 1.981 kg/kW
- BMW M Hybrid V8 - 2.034
- Cadillac V-Series.R - 2.045
- Acura ARX-06 - 2.079
- Porsche 963 (2025) - 2.107
- Porsche 963 - 2.259
Aston Martin remains at the most advantageous level, one that the Valkyrie LMH has enjoyed since Sebring. The 2026 Porsche 963 is still held back in low-speed BoP after its higher rating for the 2026 Rolex 24.
Compared to Long Beach, the following changes emerge:
- Acura ARX-06 -0.038 kg/kW
- Porsche 963 -0.033
- Cadillac V-Series.R -0.025
- BMW M Hybrid V8 -0.023
- Porsche 963 (2025) -0.016
- Aston Martin Valkyrie +-0.000
Here, Acura gets the biggest break. While only receiving a 3-kilo weight break, the ARX-06 is allowed 7.8 kilowatts more power, leading to more punch out of tight corners like Andretti Hairpin, Corkscrew and the final corner at the Laguna Seca Raceway.
The 2026 Porsche receives a 0.033 kg/kW better power-to-weight ratio, which, after its monumental hit ahead of Long Beach, still puts its weight far above all other GTP cars.
The two Dallara-based LMDhs of Cadillac and BMW receive a smaller break, with the 2025 Porsche receiving the smallest improvement following an encouraging performance at Long Beach.
In comparison to the BoP at Laguna Seca Raceway in 2025, the following picture emerges. Keep in mind that all LMDh cars except the 2025 Porsche have been updated over the winter:
- Cadillac V-Series.R -0.099 kg/kW
- Porsche 963 (2025) -0.056
- Acura ARX-06 -0.033
- Aston Martin Valkyrie -0.004
- BMW M Hybrid V8 +0.042
- Porsche 963 +0.096
Cadillac gains nearly 0.1 kg/kW compared to last year, with the 2025 Porsche also receiving a big break. BMW, which had a very favorable power-to-weight ratio of 1.992 kg/kW back in 2025, has been reeled in again and brought to a similar level with the Cadillac V-Series.R.
Of course, the 2026 Porsche 963 is still way above all power-to-weight ratios seen in 2025 and so receives the biggest penalty compared to last year.
Above 200 kph: Porsche now on top
After the 190 kph threshold, the picture begins to swing in the completely different direction: From 200 kph onwards, the Porsches receive the most favorable BoP, of course behind the relatively draggy Aston Martin Valkyrie, which is still clearly in front:
- Aston Martin Valkyrie - 1.981 kg/kW
- Porsche 963 (2025) - 2.079
- Porsche 963 - 2.085
- Acura ARX-06 - 2.087
- Cadillac V-Series.R - 2.089
- BMW M Hybrid V8 - 2.100
For the first time this year, BMW gets the least favorable power-to-weight ratio, albeit the five LMDh cars are being kept inside a small corridor of 0.021 kg/kW, as IMSA had envisioned over the winter.
Changes compared to Long Beach:
- Porsche 963 (2025) -0.044
- Porsche 963 -0.031
- Acura ARX-06 -0.010
- Cadillac V-Series.R -0.006
- BMW M Hybrid V8 -0.001
- Aston Martin Valkyrie +-0.000
Given what happened to the Porsches ahead of Long Beach, it is no surprise to see them receiving the biggest break in the high-speed sections now that they enjoy the best power-to-weight ratio in this area of the LMDh cars.
Even BMW’s BoP is slightly improved to Long Beach, but gains of other cars leave their GTP with the worst power-to-weight ratio above 200 kph.
Changes compared to Laguna Seca 2025 - again keep in mind that all cars except the 2025 Porsche and the Aston Martin LMH car have received updates over the winter:
- Aston Martin Valkyrie -0.063
- Porsche 963 (2025) -0.015
- Porsche 963 -0.009
- Acura ARX-06 +0.004
- BMW M Hybrid V8 +0.007
- Cadillac V-Series.R +0.045
The Aston Martin, which was still a relatively new car at Laguna Seca Raceway in 2025, receives the biggest break — by a wide margin. No too many changes have been made to the Porsche models, Acura or the BMW.
There is, however, a notable change to the low-wing Cadillac V-Series.R in the high speed sections compared to 2025. Having enjoyed a relatively favorable power-to-weight ratio in 2025, it has now been brought back into line with the other LMDh cars.
Conclusion
Only Laguna Seca will show how much the Penske-run Porsche 963 will suffer from their BoP hit they received for Long Beach. On the tight streets of Long Beach, the Porsche's weight penalty hadn't yet shown its full effects.
Laguna Seca raceway with several mid-speed corners will paint a much more realistic picture in this regard. Porsche is set for a tough race. The same, however, was said ahead of the 2025 race which Porsche won with a 33-second margin.
Given its recent victory in Long Beach, Acura looks good on paper to return to Victory Lane, but might face a strong challenge from Cadillac, which has gained a huge BoP break in the slow-speed sections.
BMW is a little bit of an unknown, given the far-reaching updates of the M Hybrid V8 and a new operating team. The numbers don’t really speak for BMW, but here are many factors at play.
And Aston Martin? With the BoP rectified since the start of the season, the Valkyrie should play a bigger role at Laguna Seca Raceway compared to the first few races of the season.
Balance of Performance Laguna Seca in detail
Values in parentheses = Change from Long Beach 2026/Laguna Seca 2025
Acura ARX-06
Min. Weight: 1,056 kg (-3 / +4)
Max. Power <190 kph: 508.04 kW (+7.80 / +10.04); 681 hp
Max. Power >200 kph: 505.96 kW (+1.04 / +7.96); 678 hp
Max. Engine Speed: 9,512 rpm
Max. Energy per Stint: 904 MJ (+3 / +8)
Fuel Replenishment: 22.600 MJ/sec (+0.075 / +0.200)
Aston Martin Valkyrie
Min. Weight: 1,030 kg (+0 / +0)
Max. Power <190 kph: 520.00 kW (+0 / +1.00); 697 hp
Max. Power >200 kph: 520.00 kW (+0 / +1.00); 697 hp
Max. Engine Speed: 8,400 rpm
Max. Energy per Stint: 913 MJ (+0 / +6)
Fuel Replenishment: 22.825 MJ/sec (+0.000 / +0.150)
BMW M Hybrid V8
Min. Weight: 1,042 kg (-17 / +6)
Max. Power <190 kph: 512.20 kW (-2.60 / -7.80); 687 hp
Max. Power >200 kph: 496.08 kW (-7.80 / -23.92); 665 hp
Max. Engine Speed: 8,000 rpm
Max. Energy per Stint: 902 MJ (-6 / -3)
Fuel Replenishment: 22.550 MJ/sec (-0.150 / -0.075)
Cadillac V-Series.R
Min. Weight: 1,043 kg (-15 / -16)
Max. Power <190 kph: 510.12 kW (-1.04 / +16.12); 684 hp
Max. Power >200 kph: 499.20 kW (-5.72 / +5.20); 669 hp
Max. Engine Speed: 8,800 rpm
Max. Energy per Stint: 901 MJ (-5 / +6)
Fuel Replenishment: 22.525 MJ/sec (-0.125 / +0.150)
Porsche 963 (2025 Homologation)
Min. Weight: 1,052 kg (-8 / +3 vs. 2025 Factory)
Max. Power <190 kph: 499.20 kW (+0.00 / +14.20 vs. 2025 Factory); 670 hp
Max. Power >200 kph: 505.96 kW (+6.76 / +17.66 vs. 2025 Factory); 678 hp
Max. Engine Speed: 8,158 rpm
Max. Energy per Stint: 895 MJ (-11 / +13)
Fuel Replenishment: 22.375 MJ/sec (-0.275 / +0.325)
Porsche 963 (2026 Homologation)
Min. Weight: 1,084 kg (-16 / +35 vs. 2025 Factory)
Max. Power <190 kph: 479.96 kW (+0.00 / -5.04 vs. 2025 Factory); 644 hp
Max. Power >200 kph: 520.00 kW (+0.00 / +31.70 vs. 2025 Factory); 697 hp
Max. Engine Speed: 8,158 rpm
Max. Energy per Stint: 891 MJ (-22 / +9)
Fuel Replenishment: 22.275 MJ/sec (-0.550 / +0.225)
