If you look up reviews of the Splice, it doesn't look much of an improvement. Used shocks can be a crapshoot. People often sell things when they don't work properly anymore. Nor should you invest wads of cash into a $600 MSRP bike.
Problems like you're describing are often fixable. I would see if that's possible before trying spend my way out of this minor problem. Take it to a shop and ask.