I put these in about 3 years ago, w/out the fancy cover plate of course. They sound great, but then again I'm not running any bass through them...
Blaupunkt GTx462 4x6m 2-way car speakers For metric 4"x6" openings in European vehicles at Crutchfield.com
I think you can still get them from either SonicElectronix or some BP outlet in Indiana somewhere if I remember correctly