You're kidding, right? The stock BPV is the best performing BPV you can buy. Anything else can't be considered an "upgrade", only "different" and actually "inferior" in function.
Most change it out due to a desire for a different sound based on the F&F movie series and the WRC racing series. There is also a misconception perpetuated by these forums that the OEM BPV somehow "leaks" boost and you get more boost with an aftermarket BPV. All pure BS. There was likely at least one that was actually faulty and instantly all the OEM BPVs are crap.
All said though, if the plastic OEM is physically broken a new one is quite expensive from Mazda.
mine was one of such "rumored leaky" stock BPVs. rare i know.
i had a DH, monitored and recorded boost levels.
It could NOT hold the comparable boost that others could... slow leak.
Also, i am not a big fan of plastic internal BPVs/BOVs, never have been.
Thats also why i did my research and steered clear of HKS. people love those for the sound, but they are metal with plastic internals, no better than stock construction.
Yes, stock ones will essentually perform best... like stock brakes, and a multitidue of other stock parts.
But since i discovered mine leaked, i went ahead and got a full metal internals BPV, the Turbosmart BPV... not the hybrid, im not super hung up on sound either, just reliability.
And yes, i also agree TOO many people just assume their stock BPV leaks and "doesn't perform as well" as aftermarket.
I kinda smirk errytime local club members tell me they had to go back to stock BPV to go into dealer, and thus felt all sorts of turbo lag, and boost leak!! talk about placebo affect. rofl.
