Robert,
I have a 56TF and just this week ordered a Heidt's Deluxe MII IFS from CPP off Ebay. I ordered the stock spindles because I wanted to keep my truck realtively stock height. The stock spindles drop the truck about 2 inches. For me that's acceptable.
My research found that most IFS units drop the truck about 4 -6 inches. More than I was looking for.
Hope that helps.
Paul