As far as comparing sound, depth and distortion, the previous owner had Polk db401 units in the dash, and the sound is comparable to my current Polk DB461 units, not as rich though, if that makes sense. Better mid range for my listening. I will try a set of Reference 5.25" Infinitis I have to compare just to see what sounds better for me. Solid installation and base, while cancelling out any vibrations in the dash is one of the things I can highly recommend. With the Sony XA AVX3000 unit I have the 55w x 4 output is pretty decent all considering