Not too sure, i didnt really look into it myself. Might need too. Personally i suggest doing entire exhaust system at once, just my 0.002$ on that.
Mufler is a different story though
I recommend you do the brakes! I find it more important then HP. Its a really good idea,
Get ceramic pads, they are an absolute must! Rotors, if you want get them later, after the winter. Or when your wear outs, but pads are a must!
I did mine for 300 installed.
EBC Red are great british street/race pads, i love them.
Personally, headlight are a good mod, if you dont like yours....tahts like 2 extra Hp and 30% more awsome.
I dont really know anything else that would be good for you before the chipping. The rest of the parts such as clutch and what not do it when the old one dies. Do those kind of mods when need to.
EDIT: BTW make sure your CA intake is safe not to suck in water, pretty easy around these times of year.