I'm just going to post it here because a question was asked on the mazda3 forum and It will be helpful here (copied and pasting my response)
They don't sell directly from their website, like many part manufacturers. Since the m3 stuff is brand new it might take a minute (or some searching) to find a US vendor for them. I buy my ultra racing stuff from the ultracing vendor on ebay; (good price and free shipping) most likely he/she can get the parts if you supply the part #. These are the guys I use.
ultraracingmy on eBay
I've noticed a lot of new vendors selling UR stuff on ebay now, it's worth it to ask around if they don't have something posted, I know "ultracingmy" doesn't sell knockoffs though, I'd go with them. Something to keep in mind when buying parts that aren't US.. They don't release cars "1 year ahead". So If you are looking for "Generation 3" Mazda 3 parts, it will be 2013, not 2014. Also, it won't be referred to as "Gen3" most likely, rather it will be called by it's generation NAME, BM, so USA 2014 Mazda 3 is actually 2013 Mazda 3/Axela BM (Gen3). "Gen 3" Mazda 6 is "GJ", year 2012. This is good information wether you are dealing with ultra racing or some other JDM/Euro/Asia supplier (UR is Malay).
