My sitbones are 130mm center-to-center (not sure if your measurement is outside or center), and I had a major, chronic saddle sore and very sore "inner bones" (don't know the proper name, but they are NOT the sitbones, but bones farther in on the pelvis) from, I now know, riding a too-narrow saddle where my sitbones were perched too close to the edges (~140mm). I am now on a Terry Butterfly (160mm, I think) and doing great. I'd definitely recommend you stick with the 155 mm Specialized saddles or something in that width range rather than going much lower.
Good luck!
Emily
2011 Jamis Dakar XC "Toto" - Selle Italia Ldy Gel Flow
2007 Trek Pilot 5.0 WSD "Gloria" - Selle Italia Diva Gel Flow
2004 Bike Friday Petite Pocket Crusoe - Selle Italia Diva Gel Flow