I replaced the stock front speakers that were blown with Polk DXi 6500 components at Best Buy... Probably more than you want to spend... But they sound great with the stock head without additional amplification. Not earth quaking loud. Loud and clear enough for my tastes... Like Pink Floyd and early Genesis.
I am about to replace the blown rears with Polk 650 2 ways... about $ 150.00 INSTALLED at Best Buy. The installer says he can make them fit after reviewing Little Beast's excellent post referenced in #4... Above.
Thanks LB!!!
Jeff
2001 Dragon, 2-90 Celica AllTrac Turbos, 1997 4 Runner