Hi, I have the M3 Turbo S and I upgraded the main capacitor parts and the resistor. I replaced the 6.8uf caps in the mids and the 68uf caps in the bass, then replacing the resistor with a Path resistor. I used Jupiter foil type caps.
You might want to expose the crossover and take pictures. It was scary for me, since I'm not familiar with electronics, but I can solder a little.
Huge impact, Highly recommended, just buy the best caps you can afford. Eventually I also replaced the wiring to the speakers with anti cables wire, and I used Duelund silver wire for the tweeters.
Good luck!