I like the design as well, nice layout using phpbb. Not too garish on the colours, the dark tone more mature to the audience you'd expect.
However my main comment on how successful you will be with this one doesnt matter about your design, or your concept subject, as there are plenty of gearheads out there.
What I would advise, is you must keep focusing on mod/admin and keeping a strong sense of community, knowledge base and friendship. This needs to be done from a new user registering and posting.
This can be seen using jupitermedia/internet.com (his sites sister sites) as an example. Some sites like web dev are popular, some, even though they have the same company behind them, just dont have that close knit community, so less visitors ...