I have absolutely the worst chair at work and it kills my back, the seat in the Solstice doesn't help me much either. I went in search of some kind of pad or support to help with this. Seemed easy to try Amazon, they sell everything else. I found the Angel Sales PosturePro Lumbar Support, read the reviews and most people seem to love it. It is only $13 with free shipping so I ordered one for the car and one for work. Well it is very light weight and fits just fine in the car and on my chair at work, the strap on the back could be better, maybe a belt instead of elastic so you could tighten it up but it works very well it fits in the car very easily and you don't need the strap, made my drive to work better for sure. Worth every penny of the $13 I spent. I almost forgot, this will be great in the summer with the top down. It creates air flow behind your back, should help relieve monkey butt.
Here is the write up from Amazon
Product Description
Protect and support the lumbar area of your back with the PosturePro. This lightweight support gently cradles your back and encourages correct posture. Ergonomic design gives firm and comfortable support while breathable mesh material circulates air to keep you cool. Elastic bands stretch to fit most standard-sized desk chairs. Slip the PosturePro over car seats for a more comfortable ride. Perfect for long hours of sitting, while traveling, working, watching television, sewing, scrapbooking, reading and more. You'll want several, for the office, home, car and RV.