~3360 lbs. That's not much for a car with a big V8. With the intake in the valley, we're likely to see a supercharger, not turbos, which is a shame. And it will still be slower 50-70 than the ipace.
The steel frame front V8, rear T-56/Getrag trasaxle Z06 with a full sized 12v battery weighed 3080 lb at the track scales (1/4 tank, mats and loose items removed, no water in wipers). The aluminum frame, more composite intensive V8, with tiny battery, has been gaining weight.
They use superchargers to reduce lag. GM has been selling turbo cars since 1962 and their newest design, the Blackwing DOHC V8 is twin-turbo as is their ATS-V, CTS-Vsport, & CT6. Even their base i-4 275hp engine for the Camaro is turbo. But with the LT2's 490 hp at year one with 6.2 liters, you might actually see the next power bump by using the 7.0 rotating assy, which could reach as high as 580 hp with no additional weight or packaging except bigger coolers. One of the wonderful things about the LSx engine is it's abundance of instant torque and it's light weight. No other gas engine has the instant low rpm grunt of the LS engines. Putting turbos on or supercharging will increase the weight, size, and lag.
BTW - Many thought the Blackwing DOHC turbo V8 was destined for the C8, but weight, cost, size, and responsiveness probably keep it out of the running for now. Another thought was a variant of the 3.0 liter turbo V6. They made the right choice by sticking with a naturally aspired high torque design for this kind of application.
The EV drive in the I-Pace is superior in power delivery, but not in shear hp quantity. From our experience with the supercharged 556? hp CTS-V and 638 hp ZR1, the surplus ICE power is only useful on a track and tends to draw too much attention for public use. The I-Pace is far more responsive on public roads than any gas engine I've experienced and has no drama associated with it. And the format of a 2 seat sportscar or even a 2+2 coupe is pretty irritating for daily use. You have crap visibility, low passenger/cargo ability, might as well ride a motorcycle.
However, if you look at the frame design of the C8, you will notice it's triangulated up front and has a mount for a differential or EV drive. I would not be surprised to see an AWD KERS PHEV variant.