i need some help and some advice and best options.

ive just got my first escort turbo its a mk5 cabby and to be fair its a bloody animal its running 270bhp rolling road graph there for proof.it's got a slight oil leak i thought it was leaking out the intercooler but sombody just said somthing about a return pipe???Whats the best oil to use for it aswell ive also been told it has to be good oil and it will just pass threw the turbo seals????whats the best way to avoid blowing it up (not like it get's ragged)ive had a good run yesterday and i didnt dare take it about 5.000rpm for some strange reason just need tips ect..