LMS soft 93 octane tune,Catless dp's,CAI. Sputtering to no avail change the plugs, change the upstream oxygen sensors both were black and found oil all on the rear turbo yesterday.also found plugs and O2 sensors were black with very heavy suit. Last time I inspected the O2 sensor it was clean Plugs in photo only have a few thousand miles on them. Want to know what to check next and help would be appreciated. Any suggestions. Sent from a form of communication,at nearly the speed of light using the internet.