you can get these on auctions for cheap, I would recomend a tomei sump, I personally prefer stainless steel than cast alloy, as it's better to bend the sump instead of cracking it in pieces if you get in an accident or small rock chip, also the cast alloy sucks because of the threads on the oil drain plug, also tomei still offers them brand new!
If you don't mind chinese parts you can get a brand new stainless steel baffled and larger capacity sump for the sr20 too, I think you can still get the greddy type too.