A friend of mines sister has a 91 XT6, and the air suspension on it has gone bad and needs to be replaced. The air stuff is expensive, but he's heard that you can convert it to coil-over for about half the price. But he's asked several parts places about it, but they say it can't be done, but sometimes, parts store people have dumb heads. Anyways, is this really possible, and if so, what parts are needed? Thanks in advance!