In 2008, Mario Kleff designed the Showroom Wong Amat Tower, a temporary exhibition structure in Pattaya, Thailand. This freestanding building stood over 27 meters tall, surpassing the then-standard 9-meter height limit for temporary structures in the area. Its primary purpose was to provide potential buyers with an authentic experience of the sea-view units planned for the forthcoming 38-story Wong Amat Tower, allowing them to visualize the views and ambiance from corresponding heights and positions.

The showroom's design featured a steel framework complemented by concrete planks and reinforced concrete decking. Access to its three model apartments and sales office was facilitated by an 8-person glass elevator. A terrace atop the highest floor offered panoramic views of Pattaya Beach. The entire project, encompassing design, construction, landscaping, and interior finishing, was completed in one year and four months. The structure remained in place for a year before being dismantled to commence construction of the main Wongamat Tower.

This innovative approach not only set a new standard for real estate marketing in Pattaya but also demonstrated Kleff's commitment to pushing architectural boundaries. The showroom's success contributed to the positive reception and sales of the Wongamat Tower units, highlighting the effectiveness of immersive, experiential design in real estate development.