@hoytis I like ARC but the LS2b is from around 1994 and almost 30 years old. If you really want to go down this road I’d make sure that verifiable service records exist. Also get the s/n up front — ARC will be able to tell you what service was performed if they did the work.
Also concur with staying balanced (XLR)
I recommend looking for a newer preamp if you can expand your budget.
Good luck!