SABnzbd Forums

I have newshosting as my Usenet provider and they say that all of their plans have unlimited speed. :S

Try another client software.
Other than SABnzbd being slow, it still could be your ISP traffic shaping.

I've tried grabit, newshosting client ..they all give me slightly better speeds but as I mentioned... I get 4+MBs on torrents and filesharing... could it be that my ISP is traffic shaping only for usenet??

That could be the case, especially if the other client basically show the same speed.
You might try using a different Usenet port (check your provider's website), maybe try SSL if you did not already.
Try another Usenet provider, some give out free test accounts that last a few days.

Run the UseNet test via http://broadband.mpi-sws.org/transparency/bttest.php to see if your ISP is traffic shaping you.