BBS North America
Since I picked up my LM’s used, I needed to get a hold of the TPMS adapters since the previous owner didn’t have TPMS on his vehicle. Tire Rack was of no use whatsoever - they weren’t even aware that BBS had an application in 20×10.5 for my car (actually made by BBS Japan) so I called BBS direct myself. One thing of note is that when you first call in, the receptionist asks “For Racing or Aftermarket” - VERY COOL 
You know these are real deal badass wheels, not some weaksauce preschool shit (360 forged*Cough). The rep that assisted me was very knowledgeable - even going as far as ensuring that I DID in fact need them, always nice but unfortunately not the norm in this day and age. Was able to get the adaptors out via 3 day air, overall a great experience and some friendly people. I have to say that I’m somewhat surprised with the smoothness considering how large of a company BBS is, but I guess this shows why they’re one of the best in the biz.