how about something like this Kev. -
https://www.classiccarstereo.co.uk/hidden-audio/hidden-bluetooth-amplifier/- you would need to add some decent (car audio) speakers which could take a bit of
finagling, but worth it in the long term.
I mounted an additional two speakers on the rear 'firewall' of the Aero (as well as upgrading the front two).
It was a little un-nerving ,attacking the alloy panel with a Dremel cutter to create the mounting holes , but turned out well
My reasoning was that you get to (predominantly) hear the rear two at low speeds and the front two when
'pressing on'.I think that you are inevitably going to need some serious amplification to achieve the necessary volume levels......
James
