The principles of AMS Plastics, Inc., the Plein Living Trust, purchased the Rancho San Diego Professional Plaza located at 3322 Sweetwater Springs Blvd. in Spring Valley, CA for $1.9 million. The buyers paid approximately $119 per square foot for the 16,000-square-foot office building, which they plan to occupy as the administrative offices of AMS Platiscs, relocating from the Rio Vista Building in Mission Valley. The company has manufacturing facilities in Tijuana and Mexicali. Christine Kugler of Inland Pacific Commercial represented the buyer, as well as the seller, Harold and Wanda Birdwell.