[lsversaw]

My 2 cents...

Putting stereo speakers, a cupholder, and seating for a third person in the seat, between the driver and outboard passenger, sounds like a challenge. I love challenges, but I would separate the speaker mounting requirement from the cupholder requirement.

Here's a way to do that: put your speakers in the rear cab corners, possibly using brackets made by forum user bigblock73, AND/OR put 2 speakers behind the center grille in the dash using the mounting plate available from forum user Kyle@FTP. Or you can build or buy kick panels with speaker mounts, but the left speaker may compromise access to your parking brake pedal if you have one. Or cut holes in the doors for speakers.

Then you can buy a center console that sits on the middle of the seat from a number of vendors, or you could go as far as finding/building a seat with a built-in fold-down console. When carrying a third passenger, with the console folded up or thrown in the bed, just ask the passenger to hold your coffee. Ha.

And you can buy a cupholder that mounts to the dash in the ash tray hole. No new holes, no muss, no fuss. And full seating space.

I hope this helps.