Stock front speakers? They were weak to begin with, so it's not a suprise they're worse now. Even many no-name brand speakers are better than the stock ones.

The stock wires are pretty light gauge. They'll work, but they're not optimal.

Adding rear speakers are good - more speakers, more sound. :)

You can almost always benefit from an auxillary amp, but if you're not cranking it that loud, such is not necessary. It will depend on the speakers you purchase and their efficiency. Do note you have limited depth in the front doors too, so choose carefully.

-- Kane
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Blossom II - '91 745Ti/M46 ... Bubbles - '74 144GL/BW35 ... Buttercup - '86 245GL/AW70 ... The Wayback Machine - '64 P220/M40