Here are the parts that need to be changed and the value they should be. That will get you there then you can fine tune these values to taste. Lotus1 on here has a sick sounding Plexi mod he did, Im sure he will chime in if he sees this thread.
Resistors
R7- 56K
R17-2K7
R29- 1K
R28- 470K
R31-...