The standard speakers are fitted on the lower dash behind the grills. and they are free to air,, hence the front speakers sound absolute gash. U can either make a small enclosure to house them,, or play with some pods either somewhere in the dash or by the kick panels. I know you dont want to cut the door cards up, But sierras sound brilliant when using 6.5'' up front. As for back you cant expect the 4 inchs to work well as once again they are free to air, unlike the saph which has a solid sealed section.
So I'd make a parcel shelf out of mdf cover it in fabric and put some 6x9's or 8''s onto it., That way you dont butcher the original parcel shelf.