Avalanche Performance Boost

[dex]

Need some advice here.  I've got about $600 to spend and need to know what mods will give the best performance enhancement.  So far, I've come up with the following options:

 

FIPK, Cat back exhaust, headers, or mass flow sensor.  Or some combination of the above.  Any thoughts or other options?

[gandolphxx]

FIPK is the easy first one - K&N or Volant - then cat back

 

my $.02