So I'm stuck on what else I should do to my A6
I already have the exhaust done, (Remus sport labeled 2 obx high flow resonstors)
Cold air intake.

I want to do a 3 inch exhaust I have a 2.25 right now and a chip any suggestions?
And what can I do before having to redo the valves etc.

 

3 inch exhaust plus a chip won't do anything for your car. If you are serious about the performance and really like the A6 body, then I would recommend that you sell your car and get yourself a 2.7T. Only proven power increase on a 2.8 is the PES supercharger.

 

Which gets you the same performance [300hp] as a mild chip with all stock trimmings on the 2.7