rms watts

I’m new to car audio and I’m working on improving my first car audio (2006 Toyota Camry le). So far I switched out the factory head unit with a Pioneer double din head unit. My rear deck speakers rattle when there are kicks and bass in a song so I’m replacing them with jbl’s. The speakers in the...

When trying to match an amp to subs, different rms watts are listed on subs, so do I look at the 4 ohm number, since my subs are 4 ohms, or do I look at 2 ohms, since the total speaker impedance will be 2.66 (wired parallel/series with two sets of 3 in parallel, and the two sets in series)? I...