OP, keep I'm mind that the M3 has a V8 under the hood, so different systems will bring out a different characteristic of the engine. The Gintani will bring out the deep sound of the V8, whereas the Meisterschaft will bring out the higher pitch of the V8, but both will be unmistakably V8 sounding in character. It really just depends on which character you prefer.
MODS: Meisterschaft GT Racing Exhaust / BMC Air Filter / UUC SSK & DSSR (Modded)/ RPI Scoops / Passport SRX Hardwired / Custom Wrap 3M Clearbra / 20% Tint / 50% Windshield Tint / Key Hole Delete / Matted Out Accessories / VRS Type II Diffuser / Smoked Reflectors / Euphoria 6K LED Interior Lights / Rear Fog Light Mod / 6000K HID's / 6500K LUX H8 Angel Eyes / RDash License Plate LED Kit / LED Xenon Reverse Lights
"M3 drivers have no friends"