I saw an article on the web recently that talked about the differences in the front iron and the o-ring differences. One used a white plastic oring and the other a black rubber one. The article showed how the area where the oring sits is much beefier on the S5. And it said if you did it wrong you'd have low oil pressure at higher RPM.

I have a new front iron on my build and dont know if it is an S4 or S5.

Anyone know where I found that article?

Thanks

 

http://mazdatrix.com/faq/oring.htm

 

Beautiful! Thanks, Thug!