Steven, can you take some pics please of the BC ones you have fitted.
Looking at the mfactory ones, they have a metal sheath which goes over the ball joint and locates the snap ring at the bottom of the sheath.
Are the BC ones the same design or does the snap ring sit up near the bottom of the upright as a stock ball joint would do?
Looking at pics on japshop it looks like they might even have two grooves cut for the rings.
There is quite a price difference between the two manufacturers.
The BC ones look very bling and shiny. Is that a coating which will wear off? I've never known bottom ball joints to rust TBH, but then there is now a lot more of them exposed to the elements...
The mfactory ones also have grease nipples to allow you to add grease which again, doesn't look like the BC ones do so would prolong their life span. Maybe another year. Dunno if that makes it worth the extra tho.
The Hardrace ones are the same style as the mfactory ones and a bit cheaper (no UK price tho) than the BC ones.
Special Projects Motorsports
The other question is do you have top camber arm adjusters?
I've been reading various comments on forums about these causing the bottom arm to contact with the brake disc.
It seems it might be limited to Wilwoods and HiSpecs etc but I wonder if you have a set of 282mm discs (stock ek9 part right? I'm not a ek9 owner) and adjust the camber with top arms to bring the lowered hub back more towards the vertical if there might be a problem. THe angle of the ball joint not being vertical inline with the hub, so any extention moves the bottom arm closer to the brake disc.
The last thing, I don't suppose you have the one ball joints you pulled out and a set of calipers? I need to get these for an EF and have a feeling that since no one is advertising them for the EF they must be a different size. So might need my hubs maching (assuming EF joints are smaller) to fit.
Thanks
Dave