You can reasonably call any supplier. Most of them won't bite just because you gave them a call. That's all you asked for. You didn't specify a reasonable price, and since reasonable is a vague term, especially as applied to the price of a product, the term would have definition only to you as you use it. However, had you requested a list of suppliers who would provide a custom wound coil for the same price as an off the shelf spring from a volume vendor, you would have had no response, and would have been posing an impossible problem to start with.
Custom springs, custom clothes, custom paint, doesn't matter. Made to your specification, you will not find a vendor who supplies what you want at the price you seem to prefer. So, if you know the rates of the springs you need, you can go looking among those who sell springs at volume prices, and perhaps you will find what you need. If you don't know what rate and length you need, you won't know when you find it. If the vendor won't tell you what they offer in terms you can relate to (other than price), again you won't be able to make an informed choice.
Buying springs intended for "heavier" applications isn't good enough. Heavier than what? How much heavier? Are they progressive or single rate? Tight wound or open coil? Such vague descriptions as "heavier" might be good enough for you or for 95% of the market, but I would posit that the readership here does not represent the 95% end of the market. Thus, offering seven or eight different applications is not much help to people with particular needs unless the buyer knows with some certainty what application each offering is made for (and I don't mean just the brand of vehicle), and the seller is willing to disclose the build parameters of their product.
I already suggested that AEV might not be serving their own needs to tell you the build parameters of the spring they offer. If they were customer oriented, they would, in my opinion, because information per se is not hurtful to customers and businessmen. The rate of their replacement springs is not "proprietary" information. They figured out what they need, and so can anyone else. Knowing that they don't make springs means they have to buy them from somewhere, and hopefully not from a Korean supplier. Who knows whether AEV has outsourced springs to their own build specs or simply found a supplier of a spring that meets their needs in some general sense. If they won't say, perhaps there is reason to be a bit skeptical.
There are multiple sources on the internet for determining spring rates, and all you really need to know is the weight born by each axle end, and a little bit about the geometry of your suspension. Once you have a target spring rate in hand, you can go shopping for springs, but I would not buy springs from someone who won't disclose how their spring is rated. It simply negates having determined what it is you need if you buy something based on a wild guess. Buying them from AEV, just because they say their product is "tuned for the LJ and heavier loads", makes no sense to me, especially under the circumstances posed at the beginning of the thread. If the original springs are known to be insufficient, AEV should be willing to swap out the springs at a price convenient to the customer base; certainly not at retail. If they don't want to do that they would be helping their customers and potential future customers by being up front about the differences in the springs so folks can make a choice.
