Greetings from a new 2007 Lexus ES 350 owner, and I appreciate the forum on audio improvements on a budget. Would the forum help me out on some audio questions for a non- Mark Levinson premium audio system? Based on the feedback and recommendations on this thread, I am going to replace all of the door speakers, and the subwoofer while keeping the stock head unit and amplifier. I purchased a dual voice coil 4 ohm high efficiency 10” Pioneer Champion subwoofer rated at 95db for the package shelf area in the rear, and also some 4 ohm JBL 6 x 9 3 way speakers rated at 94 db for the front doors. Does anyone know the specifications for the stock amplifier, including the watts per channel (100?), number of channels, and minimum speaker impedance? (I certainly don’t want to blow the amp up running too little impedance with the new subwoofer which can be run as little as 2 ohms) Also, I crawled inside the ES 350 trunk looking for specs on the stock subwoofer, found impedance is “2.5 ohm/2.5 ohms” and is connected with 4 wires, blue, yellow, red, and green. Is this a dual voice coil configuration? And if so, which are the positive and negative wires? The typical red and black terminals were not labeled, nor did the vehicle schematic provide any help. The Pioneer sub has a dual voice coil connection for 4 amplifier wires ( 2 red, 2 black), so I am hoping they will match up somehow. The door speakers are really simple, just plug and play, and I think I can connect these without issue. Ultimately, I plan on putting down some dynamat in the doors, and rear package shelf area, in order to reduce road noise/sound deadening. My sawzall will quickly enlarge the subwoofer hole. Thanks for any assistance or advice. I believe in the old adage….measure twice cut once!