All Classified forums require a Site Supporter subscription. It is only $25 per year and you can buy and sell whatever you like on the forum. To become a Site Supporter, go to Your Profile and select "Paid Subscriptions."
My understanding is that the 1/2 to 1 ton arms fit the same foot print. But as the wearable component grow to accommodate the higher load, the spec's change. How bad were the original arms? Bushing, ball joints, aren't dependent on the arms unless they are deformed, bent, etc..