Hey EddyxMarvoloxRiddle,
Unfortunately when Spike gets his soul as in canon, he weather comes back to Sunnydale right after and has to fight or we're on for a long separation between Spuffy like in
Sang et Ivoire by Holly or
Seven Years in the desert by Caro (WIP).
There's
Victims of Fate by ya_lublyu_tebya. On
EF and the
BSV.
Summary: Goes AU during 'Becoming'. The soul restoration spell has further-reaching consequences than anyone could have predicted, changing Buffy's life forever. And when her life begins to fall apart around her, she finds understanding in the last place she would have looked.
Anticipation by 2writers4spike On
EF, the
BSV and
FF.net.
Summary: Having no idea how it happened, Spike finds himself back in 1977, reeling from a newly acquired soul and more guilt than most could handle. After dodging Drusilla, his main focus is getting back to his own time and back to Buffy in Sunnydale so that he can atone for all he's done. That is, until he sees the newly born slayer in 1981 and goes off in a new direction. Can he stop the events that brought misery to Buffy's life, or will he be forced to watch destiny destroy the woman he loves all over again? 2writers4spike is the penname used for collaborations between dawnofme and mabel marsters
A good series where Spike got his Soul early:
The Avocation Series by Enigmaticblue. I give you the AO3 link 'cause it's the only archive where the series is complete.
Summary: Starts in S03 The gypsies curse the wrong vampire, and by the time they rectify their mistake, Spike has been fundamentally altered. Nearly a century later, the Slayer needs help, and there's only one person qualified for the job. Of course, he's not real interested in taking it.
There's also
Si Primo Venit by KittenOfDoomage.
Summary: This fic is a response to a challenge on Elysian Fields from _G0tik4_ which I was intrigued by and then an onslaught of spare time between phone calls created the following. I'm thinking this one may be longer than my regular fic! I am warning now, there will be multiple pairings in this fic, as well as canonical ones. There will be Bangel, allusions to Spike/Darla, possibly some Spike/Dru,Angel/Darla,
and eventually Spuffy. This is a SPUFFY CENTRIC story, the Bangel is required to get there. So please, don't flame me. If you don't want to see Bangel, don't read the fic. It won't be graphic Bangel. I'm not a fan. It's just required here. So yeah. Meh. Let me know what you think.
Inspired by the same challenge Hold My Hand Even Though I'm a Sinner! by CheekyKitten (WIP)
Summary: What would have happened if Spike was as old as — or even older than — Angelus/Angel? Spike was sired in 1680 and is now returning (yes, returning) to Sunnydale just as a young Buffy Summers has killed the Master, but died doing it (canon, she came back lol) and as his «brother» Angel is on the verge of finding some level of peace.
Completely AU but a very good read Scarlet Symphony by DauntlessGrace
Summary: The year is 2030, and the rules have changed. In a broken world corrupted by violence, the use of all magic has been banned. But when LAPD Detective William «Spike» Pratt is called in to investigate a recent crime that leaves a high profile body in its wake, he refuses to believe the darker practices have been thoroughly eradicated from existence. Not an All Human (AH).
More rec in this thread. I'll edit if I think of anything else. 
