I'd assume you'd want the heavy duty factory style rear leaf for what you're doing...

Eaton Detroit Spring has them for around $700 plus shipping (made in USA). Took about a week and a half to get them.

ESPO Springs n Things has them for $270 plus shipping, but about a 4-5 week lead time (made in Mexico). I was more impressed with ESPO's customer service on the phone but wanted to get my car back together a bit quicker. If you search around, I don't think you'll find a complaint about them.