Ramair is a good start to let her breathe. Now custom exhaust may breathe great, of give her asthma. It'd be hard to say exactly what tune you would need without knowing how well the new exhaust will breathe. Is it a full exhaust system, or stock headers with your custom parts added after? Either way Hans would be the man to talk to unless you are going with a custom tune done on a dyno.
Please post pictures, and let us know how she runs.
Yup, I can give you something that will keep you safe (not lean) but I would suggest that once you are able to get it fine tuned on a Dyno preferably done by a operator that knows how to use TuneECU,
you will need to give me more details of the custom exhaust and your email address in a "conversation" please