It cant hurt to resize the hole..but you have to leave .100-.125 all the way around so it can seal. On the THDP its about an 1.25 hole..you have to pull the exh housing of the turbo and match it to the puck..a dremel will work fine. If you go to big..you'll be sorry..so take care.
I would tell you to try as is..and see how it goes.
Thanks Razor. Oh ya, I will have to try that cold air thing this winter when I am not driving it. I have alot of cleaning I need to do under there. Thanks again.