When I did mine I didn't get my ypipe seated the first time. No boost and rolled so much white smoke you couldn't see the intersection.

Find source of leak. Sometimes if you pull in dark shop or at night and use good flashlight it's easier to see source as you are checking. I'm told the covers on oil coolers are prone to cracking

Correct me if I'm wrong but would the clamp on the map sensor being off cause it to run rough I think it runs a hair better now that I put the clamp on and now I need to get up pipe and down pipe lined up perfectly ..... You guys ever try putting a 4in down pipe on and lining it up WHAT A PAIN IN MY ASS and for the oil I don't have a clue where that's coming from but when you get done with everything dosent it start rough for a few days or first 10 times or so cuz it sounds rough as fuck starting!!!