Any ideas on what to do to my car next?
 

I have an 01 Audi s4 with k04 turbos and a APR race tune setup in it, I'm wondering what else could be done to my car, like how to run nitrous with a chipped car that advances my fuel ratio already, or just any ideas on ways to get more power. My goal is atleast 500-600 hp and around the same ftlb's of torque. I'm thinking that I have around or over 400 ftlb's of torque right now with around 350 hp with my current setup, but I'm just looking for more, thought I would ask the experts, so any ideas?

p.s. I am looking for wide body kits also, and mayb some interior mods, so any input on what you think looks cool on an 2001 Audi s4 go ahead and put down, thank you.

Is all that you have done a chip and k04s?

Yeah, I'm just wondering on ideas for what to do next, and I'm not sure how to hook nitrous to a car that's already chipped.