1955 caddie sound system suggestions

Hi. I've got a customer with a 1955 caddie who wants us to install a "great sounding system" We cannot change or modify any original panels or equipment as this would seriously decrease the value. I couldput subs in the trunk but this customer wants foot tapping bass (not heavy) and crystal clear highs. I'm afraid the tight bass will get lost in the trunk. If anyone has ever touched anything similiar or has any suggestions, I'd appreciate it.

Havn't done the exact car but have done a lot of classics. The bass should be fine in the trunk but bring lots of dynamat as it will rattle. I would suggest a rear firing sealed enclosure. Head unit wise I would have recommended Custom Autosounds stuff, but since they got rid of their Kenwood clones the sound quality has dropped off. I would get a quality remote controlled HU and PAC's IR repeater in the glove. If you have glass skills I would build kick panels for components.There is no such thing as free installation!