Just to check, when you say 4-wheeled G63 AMG from around the same time, do you mean the second-gen G63 AMG that came out around that time?
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As I think this is the first time we are hearing about it being modeled back in the day, unless my Dory-like memory is forgetting something here![]()
It's listed as a 2018 model, so not the second-gen car. It's a bit superfluous since the 6-wheeled G63 and the 4-wheeled G65 are already in, which is probably why it's never seen a release. Like most unreleased cars, there's no guarantee it was actually modelled, but it was planned to some degree.
There are plenty of minor variants that don't get used or get replaced by something newer, like the 2016 LC500 and 2018 RS3 saloon, so the G63 is probably one of them.