Bro seriously just get them off of ebay from one of the big car audio power sellers with the best feedback.
Or get them from crutchfield.com and pay twice the price
Rear speaker are held in place by that wire basket
I would run a higher end 4X10 instead of 6X9 and an adapter. A higher end 4x10 will blow away the 6x9 in SQ and SPL and you don't have to worry about creating an accidental bandpass effect. IMO, if you want bass, don't try and get it from a little 4x10 or 6x9, install a small sub in the trunk.