How can I decrease the amount my Chevy HHR squats in the back when I load a powerchair on my external carrier.

I installed a class 1 hitch onto my 2006 Chevy HHR (no problem), this is to allow my to load my son's power wheelchair onto a external carrier (with loading ramp). The hitch works great and is well within it's load rating. However, my vehicle ';squats'; about 4 inches when I load the chair. It weighs about 160 lbs total, the carrier weighs about 40 lbs.

Should I change springs, shocks, leaf springs? Not looking to completely eliminate the squat but would like to reduce it by 75%.How can I decrease the amount my Chevy HHR squats in the back when I load a powerchair on my external carrier.
You can actually have airbags installed in between the leafsprings and frame of the vehicle. The air bags come with a small air compressor that is installed underneath the vehicle and inflates and deflates the bags from a control unit inside the vehicle on the dash. It will probably cost about $200-$400 for an airbag kit installed. Firestone actually manufactures the bags which are very durable and will last you a very long time. This will also help to releive some of the pressure the wieght is putting on your leaf springs and rear shocks. It is the best way to go because you can control the height of the rear of your vehicle from inside of the cab of your car. The air shocks that other people talk about require you to physically hook up an airhose when you want air in the shocks and physically let the air out when you don't want the shocks so high..I would not recommend these as they are a pain for someone in your situation where you are constantly changing the rear height of the vehicle. The air shocks were developed for street and drag racing assuming people would only make adjustments during racing, not everyday driving in which the rear load would dictate at what height you want the rear to be. Again, I would stay away from the air adjustable shocks and look into installing airbags, much more efficient and adjustments are made on the fly from the comfort of the cab of the vehicle. Good luckHow can I decrease the amount my Chevy HHR squats in the back when I load a powerchair on my external carrier.
I bet there's an air shock kit that would be perfect for your situation. Your dealer may even be able to help you out, or else go for an aftermarket supplier.
your best bet is go back to the 70's thing and get air shocks -they now have pc controlled levelers on them -expensine but work well-other wise do the air thing yourself