I've installed a set of Airlift 1000 into my 1022 Toyota Sienna EXL just 2 months ago. I was easily able to install them using only drive-on ramp stands, without using a commercial jack or even dropping the wheels or removing them. There's a plastic ring protector for the bottom of the spring, then install the deflated airbag into the spring, from a gap near the top. It's a bit tricky installing the air hose in the bottom, but I used a hemostat, like a pair of locking needle nose pliers, to pinch the clip and slide it up to the barb. I ran the hoses to a tee and then put the schrader valve near the trailer hitch. It pumped up fine and has held 30 lb pressure for the 2 months.
I have not used the Sienna to tow with yet, but have noticed that the headlights stay lower even after heavy loading.
My previous 2004 Honda Odyssey benefited well with the same Airlift configuration and do feel that, at under $100, it's definitely worthwhile for towing my Bigfoot
Go for it!