If you do decide to go with new housings check out RHDJapan.com
https://www.rhdjapan.com/jdm/Mazda-O...-13B-REW-12978
They have good pricing usualy, also check with Ray Crowe at Malloy, I'm not sure what his current pricing on housings is but he also has very good pricing. Or one more option they are trying to start a group buy for housings with RHDJapan you could possibly wait and get a really good deal through that.
http://www.rotarycarclub.com/showthread.php?t=541