Mods you will definitely see make a nice improvement all round

ST170 Manifold
Full Cat Back
Decat
Enclosed induction kit e.g. BMW or Pipercross Viper
Aggressive cams (mild ones generally spoil mid range and don't add too much on the top whereas a slightly more aggressive profile means you still get some lacklustre performance low down but nice BHP gains on top!)
With cams you generally want to do vernier pulleys and under drive pulleys as well help things go a bit better!

After that you'd be looking at throttle bodies or a supercharger!

As for mapping in my opinion don't go with bluefin, see MSD for a generic chip or have one modded to match.