if you go for 2ltr cams you'll need the 2.0 ecu as well.
supercharging, turboing or throttle bodies will give nice performance gains at a price.
upgrading the brakes to the mk3 mondeo ones (260mm to 300mm) is an easy job for the fronts and a bit more involved on the rears. for a bit more work then the asbo focus brakes will fit with Focus RS 324mm 4-stud discs but check your rim clearance. there are lowering springs/kits available which will help with the stance instead of it looking like its on stilts.
take a look on MEG (now talkford) there's a wealth of info on there.