ok, so in the near future (withing 6months) I am planning on buying an '04 mustang GT. and of course I will want to improve it as much as I can. I wanted to know if you guys had any tips/ideas on what I should get started on first. I'm looking for a general all round performance, sound, horsepower, mpgetc. I wanted to start with the exhaust and go from there. Do you guys have any advise on what brands would be the best more my money. buget is a few grand. Just throw some ideas out if you want to add anything other than just exhaust b/c i will most likely change them as well.

Plan:
headers
mid-pipe
cat-back