I would like to replace my factory speakers and add a monoblock amp with a subwoofer in my 2009 Mercury Mariner. I have the navigation and sync audio system that I want to keep. I'm looking for advice on what configuration is safe but still with good performance. According to Crutchfield website, it cautions on installing anything using more than 30 amp current draw or 350 rms power rating to avoid damaging the electrical system.

My more knowledgable friends have said that this recommendation is for a straight wire, if I add a battery backup I can add more power. Rules are meant to be broken blah blah. These friends don't have a hybrid so I'm skeptical. I don't want to damage my vehicle but also don't want to skimp on sound quality either. I do care more about quality than volume, but definitely listen to my music loud at times.

Also is it ok or safe to take to a place like Best Buy for this? I am nervous about this because I just got this vehicle and I love it !

Thanks in advance for your tips/advice !