Downpipe vs. Highflow Cat.

[HotShot]

I was looking at the ZZP downpipe which includes a high flow cat. and wondered if there would be any difference between haveing a full downpipe like ZZP or just buying the highflow cat seperate from Flowmaster or Magnaflow? Is there any effect on the performance?

[DomestikDemon]

Most factory catalytic converters arent even that restrictive....many people say when upgrading exhaust to just leave the factory cat. Its up to you, but personally Id get the downpipe with the cat