Those are the Maxonform plugins.
The Architecture Exchange plugin installer can only be found on the CD you get with Cinema4D as part of the Architecture Bundle (C4D+Advanced Render+Sketch & Toon). I'm not sure if you can buy the Exchange plugin separately if you already own C4D .. depends on your reseller
cheers,
Owen Sharp
Design Technology Manager
fjmt | francis-jones morehen thorp
iMac 27" i7 2.93Ghz | 32GB RAM | OS 10.10 | Since AC5