the turkey is compressor surge, this is caused by the bad bypass valve that mazda put on our cars. to make a long explanation short, it has been there all along but the stock air box and pipes were plastic so they muffled it. When the aluminum pipes of the air intake were installed to replace the stock air box and pipes it allowed you to hear the noise. This noise is created from the bpv recirculating air and that air hitting the turbo fan in the wrong direction. The easy fix for this is to run a dual system by adding in a blow off valve while keeping the bypass valve. If your intercooler pipes are plastic this will not work but to get hardpipes can be expensive. the compromise is to buy a hardpipe for the section you need, SLS performance makes one that works from the stock side mount intercooler(
www.horsepowerfreaks.com ), all other hard pipes are designed for use with a front mount intercooler. check out this thread to see how to do the actual installation of the bov for the dual set up:
http://www.mazdas247.com/forum/showthread.php?t=40956
I will be doing this as well, i added an intake yesterday and found my turkey, I will probably replace the stock bypass valve with the forge bypass valve:
http://www.horsepowerfreaks.com/pri...ow_Off_Valves/part/MazdaSpeed_OEM_Replacement
I will then add the Forge Blowoff valve:
http://www.horsepowerfreaks.com/pri...otorsport/Blow_Off_Valves/Blow_Off_Valve_Kits
the blowoff valve will be installed on the harpipe kit I mentioned above:
http://siteground207.com/~protegeg/product_info.php?cPath=281_32_169&products_id=1362