I think you are better off buying shock absorbers brand new if you can stretch the money. you can get some bargains at the wreckers, but if you buy new they will last years, you never know when the wreckers ones are going to fail. but if they look good, and they are cheap....then i guess its worth a punt.
I suggest KYG excel G part number 343113, which suit a commodore of some kind (might be VN, i thought that this particual code suited some factory lowered version). they fit great, and they were only about $150/pair (have a chat to GSL rally sport, he is always the cheapest around)
As for springs, there was some king springs on ebay for about 130 a pair. Problem is its hard to know how low they are going to be.