My sister does speed but she snorts it, whats is the long term effect? She needs 2 stop

She does need to stop. Here's a good source of information for Speed:
http://www.urban75.com/Drugs/drugspeed.html

You should sit down with her and calmly discuss with her your concerns like two adults. Help her get off Speed. Find out why she's doing it in the first place.

Sitting down and talking to her calmly is not going to help, If it was that easy there wouldn't be addicts waiting to get into rehab. She needs professional help. For now get her to a Narcotics Annonymous meeting,

I've been taking it for 30 years, and I like it. It's fun.

Tell your sister how much you love her and that you'll always be there for her....no matter what.
Having one person in this world, who truly,truly cares, makes all the difference.
When your sister comes to you with her hidden problems, you'll be the one person who will listen and not judge her. Allow her choices, and love her anyway.
She will be made free when she sees your love is more powerful than the emptiness that drives her to speed. It may take time, but you're care will win.
If you believe in God, then pray too.
Cheers.