if you do a search you will have over 150 threads to look at....
however,, I have seen a couple of mazda speeds with bovs.. mine being one.. I had the TXS on there for about a day... running 10 psi, recirculated,, it doesnt do a damn thing.. it was quieter than my stock one, and the boost still dropped..
thre is a guy on here running a Greddy type s, and he is not recirculating it, and it sounds pretty nice..
there is also a guy running a HKS SS valve...
in my opinion, an aftermarket BOV is not needed.. Joe P (kwiktsi) has run up to almost 20 psi on the stock one and did not have any trouble.... so you might want to spend your money elswhere...