Just picked up a Toyota Highlander with the base sound system and need upgrade advice. Similar to upgrading your HT, what's the biggest "bang for the buck" ? Upgrading speakers or the heady unit first ? Also, any comments on specific manufacturers of both speakers and HUs are appreciated. Value clarity over volume, as I'm an old fart. No need for a 350+ watt sub Would like an HU that handles MP-3 CDs and XM/Syrius (still on the fence on which one). An external-connection for an ipod-type device would be nice also. The current Toyota HU is "double height" with both a CD and tape player, does this complicate my choices ? Note - new HU does not need cassette. Thanks for helping a car newbie !