AMG does.
The CTS-V engine is not hand built, it is built on an assembly line in Silao, Mexico (where they make the Avalanche, Suburban Yukon XL and Escalade ESV/EXT). The Corvette ZR1 has a hand built engine, and I have read the Gran Sport engine is hand built because of the dry sump oil system. Those are built in Michigan.
Aside from that, I see the problem as the Corvette engine is not made to be "standard of the world" in noise, vibration and refinement. A V-series Cadillac should be fast, but also refined, it is still a luxury car.
So when did AMG become Benz's loss leader? I thought that was Smarts place."A V-series Cadillac should be fast, but also refined, it is still a luxury car." That is why it has the trim/tune that it has.
Per GM PowerTrain
Overview
More than sheer performance, the LSA balances great power with exceptional refinement. Everything from the pistons to the aesthetic engine cover was carefully selected and tuned to deliver quiet performance. An advanced, sixth-generation Eaton supercharger with high-twist four-lobe rotors is a large contributor to the engine's quiet high performance. It enables a broad power band with almost imperceptible operation.
GM engineers created 370 different power simulations to optimize the LSA. It has been validated beyond 100,000 miles and has accumulated more than 6,400 hours of dynamometer testing. During testing, it was run more than 270 consecutive hours at wide-open throttle without a failure, and it completed actual and simulated 24-hour track tests.
I cede the hand built of every Vette engine my gray matter had failed me on that point though I know of no other Entry brand that hand builds any engine let alone to this level of performance.