Blue oily smoke from exhaust

[Ryan s3]

I fitted a used exhaust (cat back) although I already had a de cat with OEM rear box.
I'm getting a lot of smoke from exhaust.
I noticed it immediately....
Do you think moisture could of been inside the exhaust or the previous car it come off had a turbo problem or something?
Not noticed it before, my pcv is all new, turbo last year.
My car is in good mechanical order, just got a bit worried.
Just a new exhaust, not heavy
mechanical work ??

 

[danny_dj3]

if it wasn't smoking before you put the used exhaust on then i would say its crap left in it. it will burn out with use.