Looking to go from 15/55 to 17/57 springs in my soft top 2 door to support my 60lb winch.
Been looking at numbers. What is the difference between 68004257AA and 68004457AA ?
There is a price difference. Is one for a set and the other for a single?
I know I can get them off ebay or Craigslist.

 

I'm afraid I can't answer the #'s question but I've done a similar swap to my 2dr, a 17/18 front compo and 58's in the back and gain about a 1" all the way around. I'm also in the process of gathering parts to install a winch on the front, (in the stock bumper) too. My Superwinch is spec'ing out at 85 lbs though.
I'd be interested in seeing how thinks sit after your install. You don't however mention if your sticking with the stock bumper or going aftermarket steel. That is adding a LOT more weight. Either way as
you have not yet purchased the shocks, I would suggest going 19's in the front to support that extra weight, (or aftermarket).
Post some pic.
topbanana

 

I have an LOD Armorlite Mid bumper on the front end.
Just got a set of 17/57 off ebay. Unfortunately won't be able to do the install until things warm up around here. Still have snow on the ground.
Going to put 1/2" spacers in the front too.