[Dead Eddie]

Originally Posted by Asama

It should show the devices for example:
if somebody write in the serache box "Galaxy S4" then the search box highlight results like as "Samsung Galaxy S4"

Stopping here for a moment. What results are being displayed? Posts? Threads? Channels? Something else entirely that isn't currently tracked by the software?

There's also an implicit requirement here to translate "Galaxy S4" to "Samsung Galaxy S4". Are you also looking to track synonyms?

What happens if the user types "Galaxy S4" into the normal search box? How is that experience different?

Originally Posted by Asama

and only if the user click on the Samsung Galaxy S4 highlited result then it take the user to the s4 forum and show the device specs too.

Stopping here for a moment. So, now you've created another search box that brings back results that take you to a predefined channel. How is this better for the user than just clicking the channel link on the forum main page? It seems like it's a few extra steps.

Originally Posted by Asama

But it shoud not show the device specs if the user click on s4 forum browsing the main board.
I don't want to show the specs block forever but only if someone search for a specific device then it should show the specs block of that device otherwise not.

Displaying content based on a clickpath is possible, but it's rarely ever a good idea. If a subset of your users would find the information helpful, why not all of them? Put it in the sidebar (which is probably where it belongs) and show it by default.