Just a thought. Since 4" component speakers are not common, a 4x6 plate speaker might be able to be adapted to fit the dash location. Trimming the plate seems like it would yield a speaker pair nearly identical (dimensionally) to the OEM speakers. Or perhaps if the 4" speaker and tweeter are removable from the plate that might be an ideal cheap OEM replacement.
Polk Audio DXi460p 4"x6" plate 2-way car speakers at Crutchfield.com