6x9s into the back
Alot of guys have stuff laying around and want to use it because they already have it. Understandable!! In this case you'd be better off purchasing the right speaker rather then cutting into your car to make an outdated speaker work. You would have to cut the sail panel area to make those fit in that location.
Just my $.02 and I hope this helps!!
I personally would just stick with the size that was there in the first place.

