I don't know if either of these are what you are looking for but Spuffy don't get along at first in them and they are in college. I just thought I would give it a shot. Even if these aren't what you are looking for they are great stories.
Blue Horizons by kantayra
http://dark-solace.org/elysian/viewstory.php?sid=556&ageconsent=ok&warning=5Summary: All her life Elizabeth has done exactly what everyone expects of her. Now in her first year of college, she discovers the vast possibilities in life. But can she escape the ghosts of her past and find the courage to explore the new paths before her...including the affections of an infuriating young sophomore named William 'Spike' Giles? Complete
That is one of the best Spuffy fics in general I have ever read.
This one is also a huge fave and could possibly be it.
Unlikely Roommates by beasleysmom
http://spikeluver.com/SpuffyRealm/viewstory.php?sid=12977&ageconsent=ok&warning=5Summary: Buffy Summers is finally going to get the opportunity to have the ultimate college experience when her parents agree to let her live on campus. But what will happen when she has an unexpected change of roommates? Complete