why a lot of people are look for mivec's extractor ?? When I get my mivec engine, the first thing I was done is to removed out my cast iron extractor, put in with aftermarket extractor.
And I can tell u that, oem extractor design is base on general requirement set up, not for racing set up.
If u have mivec engine, then u can look for mivec aftermarket extractor. If ur engine is not mivec, like 4G91 or 4G93 engine; batter look back original aftermarket extractor to replace. Because different engine will different design and will provided with different output bias.
just my 0.0002 cents.