Soo i have the following equipment aot of another vehicle of mine that I recently sold and would like to install it in my 88 lx hatch.
2 infinity kappa 330w 3way 6x9's
1 Jbl 560 watt amp
1 Jbl 12" sub in a box that is 17dx20wx15h
My question is should I build a box that will fit everything in the trunk area, or should I sell the 6x9's and get some HQ 5x7's that'll fit in the stock Rear speaker locations. Any help or experience is greatly appreciated.

 

Cut out the 5x7's and make way for the 6x9's.
You'll get much better sound quality.
Buy a box for the 12".

 

The Sub is in a JBL band pass box already. The problem is I can't find anyway to mount the 6x9's on the rear dash.

 

IMO if i wanted to put speakers in the rear,i would sell the 6x9s and buy a 5 1/4 componet set and build a plate for the 5 1/4 and tweeters to fit in the stock location.But if you dont fell like building the plate or dont have the tools, just get a decent set of 5x7's.

 

Try this to mount 6 x 9"s: take out the 5 x 7"s and trace around them onto 1/4" plywood and cut out. Drill holes as if you were going to mount the 5 x 7"s to the boards. Center the 6 x 9"s as best as possible, mark and drill the mounting holes, then leave yourself a good 1/2 inch around the perimeter and cut out the rest. Good luck.

 

still puttin a square peg in a round hole. I cannot believe we are giving advise to cut a mustang to fit a 6 x 9, they ain't all that.........