Buffy and Spke are somehow involved in gangs. They eventually end up together, but Spike has recurring dreams/nightmares/hallucinations of being with Drusilla and usually ends up harming Buffy until he wakes up.

It's a rather old story, and I can't remember much else.

Could it possibly be:

Sauntering Angels by silly_bint

http://spikeluver.com/SpuffyRealm/viewstory.php?sid=21887&warning=NC-17

Summary: Buffy Summers is an average girl, head over heels in love with the bad boy of the school Spike. He's always kept to his gang until the day trouble starts to brew in Sunnydale, between two rival gangs. Buffy of course getting stuck in the very middle.

I don't remember dreams, though. Buffy's dad had a gang in LA that she was affiliated with it turned out even though at first it doesn't seem like she is a gang member too outside of being with Spike's gang. It's an old story...

There is another gang story that I loved and was never finished. I don't recall dreams in it either but I'll include it here just in case:


Playing on the Dark Side by pj

http://spikeluver.com/SpuffyRealm/viewstory.php?sid=10189

Summary: When Buffy's mother dies suddenly, she withdraws from her friends and family, and runs away from home. Venturing the streets of L.A. by herself, she is abducted by a gang when she accidentally interferes in their business. Buffy finds herself in the middle of a cruel life, where violence and rape aren't given a second thought. Can Spike save her from this life...or can she save him? A story about rape, whether redemption is even possible, and whether love can triumph from it.

ETA: It talks a lot about rape in the summary, but I never really thought of it as a rape fic per se althought there is that in it. It's a lot more than that though. I truly loved this story, and it kills me that it's unfinished.