Maybe you should post on the 4sale section
Sorry if I come across a bit one eyed but I can assure you I am not.

My advice may not always be the best but I try. I hope the following ramble doesn't come accross too strong but here goes anyway.
I work full time as a Plasterer/ceiling fixer and very part time selling 4wd stuff. I do not make much money selling 4WD STUFF. If I don't sell one more spring or shock then that would be fine. If I can help out someone with some advice or get them stuff a bit cheaper or a bit better quality than I am a happy man. If I think you can get a better deal elsewhere than I will tell you so and hopefully tell you where to find it.
I am not an expert but I speak to people who are, and I repeat in here what is said if I think it is helpful. What I have posted about progressive coils is what I have been told by those who have sold them in the past.
I havn't posted anything on the 4sale section unless it was 2nd hand, but it is a good idea so I probably will post in there.
I personally have put a pair of progressive coils in my GQ. They didn't work for me for other reasons. I got soft and softer therefore their destiny was to flex well for a while then sag majorly. This is what the guy told me would happen when I bought them from ARB and this is what happened.
The way I see it (not an expert) your progressive coil has 3/4 of it being a stiffer coil and about 1/4 of it with tighter turns to make it softer(could have thinner wire). The 4wd generally sits so the tighter coils are compressed and you get more flex because they stretch out when 4wding. I reckon a permantly compressed coil eventually will lose its recoil.
Or if the tighter coils are not compressed in its normal state when the 4wd is still, then if you load the fourby up, by the time the stiffer coils take up tention you are already sagged 2 inches (No better than the usual soft coil).
Another thought is the tighter the coil(softer) the more it is likely to sag and lose its spring tention
First up it's going to need a bit of lift to fit the 33" Wrangler MTRs that I have piled up in my backyard. Can anyone recommend a good (ie cheap) source for 2"or 3" shocks and springs plus five 15" x 8" wide offset rims fitted to the wranglers? Melbourne, north is closer but anywhere's okay if they're good.
Jason asked a question and I reckon I can help. If nothing else he has a price he can quote when he goes to his local supplier.
Suppliers don't want to sell you soft coils because they are far more likely to sag and you will then want your money back.
Happy wheeling on the weekend
Shane