Hey guys i've been saving up and now i want to spend my money wisely.which elite saber is sithy and good for duel?thanks!

It all depends on your dueling style really, as some hilts are more comfortable for two-handed or one-handed holds. There's another thread with measurements of most of the hilts that SaberForge offers, might be a good idea for you to check that out, as the comfort-zone when it comes to length differs from person to person.

SF Hilt Lengths: https://saberforgeforum.com/forum/general-store/390-length-of-sf-hilts

Nearly all sabers have the option of appearing a bit more Dark Side-ish, by adding weathering, or giving them a two-toned scheme. A nice example is the one I ordered, the Sinister Prophecy. Without weathering it looks nifty, clean and very Jedi-like. Add weathering and it immediately lives up to the design's name, becoming almost diabolic.

Sinister Prophecy: http://saberforge.com/elite-sabers/sinister-prophecy-saber

Another one that catches the eye when it comes to that aggressive, Dark Side look, is the Venom. Again as with the Sinister Prophecy, the weathering adds even more character to the hilt, making it darker and more evil-looking.

Venom: http://saberforge.com/elite-sabers/venom-saber

It all comes down to preference really, as the Obi-Wan TPM-inspired Avenger also looks pretty darn sick when you add weathering.

Avenger (weathered): http://saberforge.com/images/stories/virtuemart/product/428.jpg

Depends on what kind of "Sith-y" look you want. While weathered hilts give off a Dark Side vibe, regular finishes paired with a red blade can work if you want a "classy" or Count Dooku feel, especially the Venomous Fury.

The Juggernaut is also a great Sith hilt, though its design makes it more of a one handed saber, and that may not be what you want for dueling.

And opt for the crimson soundboard just to top it off. M-m-menacing.

I've been looking at any of the 'V' sabers. Either Venom, Viper, or Venomous Fury

I cannot wait for my weathered viper.. but. I am anyway

The acolyte apprentice saber can also look pretty...sithy. I get mine in tomorrow, but pics I've seen of them look awesome as both sith snd jedi options.