The XP's seat post locking cam has more than enough adjustment to accommodate a 0.2mm difference in diameter without shims. My Satori Animaris at 31.6mm locks as tightly as the original Lectric 31.8mm fixed seatpost. IMHO, the suspension seatpost is DEFINITELY worth it. The difference is dramatic, and now I'd never ride without one!
Bud
Bud