OK, getting tired of using my BT portable speaker, not very loud. I have the OEM radio, which I'm not going to touch, not going to cut dash, door panels etc for speakers. This is going in my '69 300 'vert. Taking measurements of rear center speaker location, I found a plastic cover for the OEM speaker. Anyways....what size speaker can I get in that rear center section, if I go that way? Looks like the 'oval' from the rear was like 6x8.5?? Under seat boxes are too tall from what I measured, and could find on the web. Here's what I'm leaning towards... Bluetooth amp mounted on some type of removeable base, (don't want to drill holes in metal if possible, locate amp in the trunk), the amp listed here would drive two 6x9 3 ways in enclosures. The enclosures could sit on floor behind each seat, or in back seat on the corners. No one rides back there anyways. The BT amp does not need a head unit. Connects via BT to my phone, stream, and control amp from phone. Speakers are 70 watt RMS 4ohm, (not worried about peak watts), amp is 100x4 channel, with bridge capability if I want to add a sub woofer down the road. Actually thinking about putting the subwoofer in the rear speaker grill area. So the 100 watts per channel should be perfect to drive 70 watt RMS, with extra headroom if needed. I know the amp is listed as 'marine grade' but can be used in automotive applications. I'm not going to car shows and entering 'sound contests' lol May go with some 6x9 Alpine 3 ways for 45 bucks, but RMS is only rated at 60 watts. So for about 125, plus maybe another 25 bucks for proper gauge wires/supplies, I would be all in for around 150ish. Thoughts, other options welcomed! Thanks!!