my friend want sell me his 4-2-1 stainless type extractor.. he said the extractor is AX Limit.. Jasma approved.

we r driving same car and same engine, (b16a auto).. but my engine is completely stock. And i plan to mod my exhaust.

He said he bought at rm8xx... now want sell it off to me rm550..
cuz im zero experience abt the second hand market price.

is it worth? or he want to con me?