Headers, cats, and sound

[Kafka]

Can anyone give me an idea of possible sound level increases when adding headers and (no race) cats? In particular I'm thinking of Supersprint Step Headers and Euro cats for my M. My exhaust changes are already loud enough for me so I would like to know what I might be getting into.

I would also like to hear from members who may be running performance after market radiators and how they work in the winter (e.g. warm up times, etc.).

Any experience/comments with any headers etc. would be useful.

Thanks.
K.