Most people think strut braces are very low bang for the buck. I have an M3 front brace, but only for access to adjust my camber plates. I would not have spent money on it otherwise.
Also, most people don't change the rear swaybar unless they have a limited slip diff.
M3 front swaybar is a really good first mod. Better shocks like Koni or Bilstein is another really good mod.