I have the LS25 and the VT100 MKII. I found that the stock PC equalled or outperformed several aftermarket PCs. However, My gear went up several notches in performance with the Elrod EPS3s on the amp and either a NBS Master III or Elrod EPS2 on the LS25. The bigget improvement was obtained when I used 3 RGPCs on the amp and the Shunyata Hydra 8 on the front end.
However, I recommend that you should expriment with different PCs if possible. In the final analysis, the selection of PCs depends on system synergy and personal preferences.