You're spring are 1.75" If you want a longer spring to put under it, which is what I think you are looking for in the YJ springs, check these out then: Holbrook Specialties Long Leafs
I don't have a set yet, but will eventually. They are around $650 for the set plus the new hangers. Sounds a little pricey but not really.
They are longer, but the center pin is offset to keep your axle where it belongs.
HTH
Erik