I have installed several "kits" lately. The BEST one I have seen so far, is from American Air Suspension.
http://www.americanairsuspension.com/CONV KITS.htm
The instructions are clear, and helpful, the ride is phenominal, and the customer service/support is second to none.
I'd rather pay an extra $25 knowing the product is superior, the company is top-notch, and I am supporting one of the best vendors the Lincoln community has ever seen.
If/when you go to install the coil conversion, PLEASE....private message me. I have very detailed instructions, with photos, and offer online-help. I also have quite a few "options" I can tell you about as far as other parts recommended while doing the conversion to save time/money in the future.
Good luck in your decision...BTW, I have both air ride, and coils. I know the difference. I know what I prefer, but your opinion(s) may vary.
My 94 is a back-roads machine(slung low, on coils)
Our 97 LSC is a comfort cruiser, but gets its behind handed to it by my 94, on the twisties!