The pic of the GX is just to show that I really did replace the 4Runner with one.
I understand that, but buyer won't care. That just looks weird. People don't read descriptions until they flip through pictures. Having the pics not match up makes it look like you made a mistake or are trying to scam or something. Hell, I thought you made a mistake.
For that same reason, I'd keep only pictures with 1 set of tires/wheels. I didn't know that you were selling both until that afterthought mention at the bottom of your post. I thought it was a mistake.
OR take some pictures with a sign depicting the difference.
"Included in the purchase price is one set of on-road, shown here, and one set of off-road, shown here".
Mentioning them as an afterthought at the end of your post doesn't help you any.
Unfortunately, you probably can't really expect any money back for the mods you did. We all know that 4Runners last a long time, but for most, a stereo upgrade on a 325k car is just lipstick on a pig. That almost falls under basic maintenance at that age (which you can't charge for)
I'd downplay (or remove entirely) the 110v adapter, and take out the mention of the rear window switch. People are hesitant (for good reason) of older cars and trucks that have had electrical hackwork done to them. No one wants to buy an old car and then have to correct all the PO's mistakes. (not saying you made any mistakes, but that's the mindset. For all they know, they'd be spending $7k on one giant electrical gremlin)
Don't mention the original cat. Everyone know that cats are expensive, and at 325k, it really is a ticking time bomb.
Just my opinion, but also don't mention the fluids. I know you're saying that 'you take care of it', but that just looks like a red flag to many. When people say they change the fluids in order to sell, it implies that they didn't change them regularly before. Means that the person didn't take care of the car. No one is going to turn down a car purchase just because they might have to do an oil change soon after.
If the timing belt has been done recently, DO mention that. That's $600+ that the buyer could put off for a while.
DO mention if you have a basic maintenance log.
DO mention if you used 4wd at least once a month; these transfer cases don't like long periods of un-use, and it can cause them to freeze up.
Overall, I'd still say drop the price to $6k and go from there.