My dash was already cut and there were already holes in the door...so I didn't sweat it too much.
I bought a low profile sub box and shimmed the rear seat up 1" with some black plastic spacers so it would fit...you don't notice it unless I point it out.
I put 5½" round 2 way speakers in the front doors...I made some side panels out of textured ABS plastic sheet and mounted 6x9 3 way speakers in them.
For the amp I put in a 2000 watt 5 channel Pioneer and mounted it under the driver seat..I had to modify the bracket for the slider in order to get enough clearance...
The head unit is just a Pioneer digital unit with bluetooth...no CD player
Really sounds clear and loud...the sub is adjustable and I mounted the control box behind the console next to the floor.