Wow, thanks for all the input everybody. Really appreciate it, I'm new on the forum. I like working on my vehicles whenever I can and always changes the coolant, spark plugs, and such myself. But I'm currently really busy in graduate school, so I tend to buy my own oil and have professionals do the actual change since I don't have the time or the luxury at the moment to get in there and do it myself.
That being the case, what sorts of questions should I ask the transmission guy to see if he understands the correct process? I've heard of the dealership process harming the transmissions on these models before. There's opinions all over the place from never change the fluid ever, to flush it, to replace it 2qts at a time etc...
They guy I'm thinking of using spoke to me for a while on the phone and seems to be genuine, knowledgeable, and old school, which I like. He went over lots of reasons not to do it, and how it could cause possible problems. But said it's a good idea if it doesn't have any issues already, so he'd give it a good inspection and then go ahead if it looked alright. It doesn't have any issues while I've driven it for the past 10kmiles or so. Any idea if all mechanics use that dealership process or what I should ask him beforehand? That process in the link would normally be doable for me, but at this point I'm willing to pay someone else for the time and knowledge if the job turns out right, instead of me using a whole weekend or more while he can do it in about a day. $160 seems more than reasonable compared to others if he knows what he's talking about. Its a transmission specific shop, not a Toyota specific one though, but he did seem very familiar with the model and the transmission.