You are pretty much spot on mate. Body lifts do exactly that, they space the body off the chassis. Your chassis rails will still be at the original height. Suspension lift lifts the whole chassis and body. Whichever way you go your diffs are still the same height, only bigger tyres fixes that.
I have never used the ironman stuff so I cant really tell you whether or not its any good. IFS stuff gets a really good wrap on here. I have IFS rear springs and Lovells front springs and shocks. Yours has a torsion bar front end, I'm not really up on the technical side of them, the other D22 guys will be able to guide you better there.