Welcome @bobzilla Are you already racing and looking for yoiur next chassis, getting started, or just curious?
Here’s a couple of topics to digest:
Here’s my observation
The benefit of “206” or what are called four cycle chassis is mostly down to convenience, simplicity and price point. They tend to be economy models with basic (if any) camber/caster adjustment, more rudimentary braking systems, steering wheels and so on. That doesn’t mean they are inferior however, just no frills.
Beyond that there’s some differences like a 40mm axle vs 50mm axles, sometimes different tube diameters but again, like I say you’ll see both types at the front of fields.
You’ll find people have been able to make almost any kind of chassis and axle size work. The four stroke specific chassis usually have two main features.
Manufacturers have “developed” chassis for low power situations, but it’s not necessary to use one and you’ll find non specific chassis up the front as well.
Rant:
Most opinions on facebook in my experience are though the lens of what a racer/dealer thinks is best for themselves or their own personal preferences… Rather than listening to the person coming into the sport and actually taking the time to understand the specifics of the person asking the question. That’s one of the drivers (pun intended) behind these forums, a place for advice that actually pertains to each situation because unfortunately there’s rarely any universal ones. Location, budget and other factors play a big part.
Long story short, a chassis marketed as a “206” is sure nice to have, certainly won’t hurt but by no means a necessity. If you can find one that’s in your budget that offers support at the tracks you plan racing at, go for it.