I never thought I would ever have a chance to host even one part of a JOC, but I’ll gladly take it. And regarding Bruno’s age by the time JOC4A takes place, I’ll use this as a reference point:
Thus, Bruno would probably be 23-26 years old (most likely on the upper edge of that range) when he bought the Stelvio V8 Twin Turbo at the end of JOC4A. And given that this first stage of JOC4 was set in the 1980s (after JOC3 took us from the 1950s through to the 1960s and finally concluded in the 1970s), having JOC4B take place some time in the 1990s makes perfect sense in my view - I just need to come up with a suitable premise, rule set, and a specific year for the setting, while also taking into account how much automotive technology and design had advanced between 1982 and the early-mid-'90s timeframe I’m aiming for.
Oh, and one more thing: I’m currently on the 4.3 open beta build, and am considering running JOC4B on that version. It hasn’t yet been merged with the stable release, though, but given that some other recent challenges also use the open beta, I’m tempted to take the plunge and make 4.3 the standard for JOC4B.