What leaf springs to buy

I have been looking around at new rear leafs for my dart. My options are the following:
$320 for mopar perf XHD
$280 plus shipping for Espo 6 leaf 1" over stock
$220 with no shipping for a pair of 6 leaf from a seller on ebay called springking.
$480 plus shipping from Eaton Springs in Ohio
$280 with no shipping from another guy on Ebay who states they are american made HD 6 leaf springs.

My question is has anyone one used or heard of the springking seller on ebay. He states that the leafs are made in Nebraska with high grade american steel. The only thing is they are listed as 3" lift.

How do the Espos and Mopar Performance XHD hold up?.

Right now the Eatons seem too pricey for me.

Lastly I called JC Whitney and they told me they do not sell springs for my 1970 dart.

Any help or input is greatly appreciated.