I'm sure most people would recommend KYB's/Koni's over Monroe's or Pedders products. When I was searching last month for new suspension not many companies had replacement shocks for NA HR34's. From memory both KYB and Koni didn't have have anything for HR34's and I'm not sure if there will be any coilover options out there either with HSD, ISC catering for ER34 but nothing listed for HR34's.
My advice, search through the suspension company websites product lists, send e-mails or make phone calls to them. Another option is to search the For Sale section on SAu and see if something come up.