[19 2SS]

Originally Posted by Idaho2018GTPremium

You're right that BMWs (and Porsches) are underrated at the crank. But the difference isn't parasitic losses due to the s/c on the ZL1: The ZL1 is rated at 650 crank hp after accounting for the power it takes to drive the supercharger. It's just that BMWs are underrated. Car and Driver dyno'd an M5 Comp and it made 617 whp. Granted, the M5 Comp is a little more powerful than the regular M5 but the M5 probably isn't that far behind.

Being underrated helps explain why the M5, a 4-door sedan that weighs 4,288 lbs can do 60-130 mph in 8.3 seconds (per C&D) and trap 129 mph in the 1/4 mile while the A10 ZL1 does 60-130 mph in 8.9-9.0 seconds and traps 125-127 mph in the 1/4 mile, despite weighing 365 lbs less, and "supposedly" making 50 more hp.

The M5 is has a lower drag coef. than the ZL1, which may explain why the 60-100 mph times are closer between the two cars, percentage-wise (3.8 sec for M5 vs. 4.0 sec for the A10 ZL1; about 5% difference) compared to the gap widening as speed grows: 100-130 times for the M5 and ZL1 are 4.5 sec and 5.0 sec, respectively (an 11% difference).

That said, have your friend watch the Throttle House M5 Competition video review on YouTube - they do a full review and they said it is numb to drive. It's very fast, but numb.

What do you mean by numb? like not very rowdy? too smooth to feel fast?