How to remove downpipe?

[Audi-RS6]

i want to gutt my pre-cats
how to remove downpipe?
any special procedures?

[vinny]

hey audi-rs6, im not sure what you guys refer to as pre-cats, but your car has 4 cats.
the two under the car are easy to get at - if you want to gut the two cats just after the turbos, then you have to either pull engine, or remove prop, loosen engine and gearbox mounts/subframes, support engine from the top and lower it just enough to get your hands in through the gaps - remove downpipes from turbos and gut away!!

[DALLAS_RS6]

Does anybody know what horsepower gain there is after gutting the cats?