This is very strange indeed. There is no apparent logic to the levels assigned.
Take for example the user
169indy who has only posted 3 times, and they are very insignificant posts at that. His title is "member".
302Z has posted 0 times and is a "junior member".
I've posted around 24 times with what I feel to be some amount of significant information and I've been assigned "stranger".
I see some people that don't even have a "supercar" and that haven't posted often & don't post any significant information, yet have titles such as "elite member", etc...
Seems peculiar.