Hello friends, Currently I am having the factory fitted sound system for my Evo which I purchased this April. Even though the sound quality of the speakers are good with decent bass, I want to install a sub woofer for some extra bass. I will be retaining all other speakers. When I enquired at Friend car accessories at Chennai, they told I have to buy converter(as head unit is OEM), amp and sub which would cost minimum 15k. Is converter really required for our head unit to install a sub? Is there any better option to install sub within 11k? Also I am afraid about installation as I heard tampering the wire may void warranty. So i wanted to install sub in a reputed shop either at Chennai or Madurai. Could you guys please provide some suggestions?