So before the flash was discontinued, I was going to purchase the upgrade re flash for the M4 exhaust. I currently just have the base flash from Stoltec. After thinking about it, I don't know what exhaust I want for sure and didn't want to be limited to the M4 in case I go the full exhaust route. So what are my options so that I can retain the Stoltec flash characteristics while compensating for an after market exhaust. Will using a piggy back controller like the power commander or Ejk affect the flash from stoltec? Also, if I download a map for x exhaust online to the power commander, will having the stoltec flash screw with the tuning of the map for the power commander since it thinks the ecu is stock? Thanks in advance.