The R22 wheel is not shown on the web site but every wheel there is described as cast alumium, one piece. They don't look like one piece wheels. All weigh in around 27 pounds, about what you'd expect for cast.
Are you sure the R22 is forged and not cast?
'03 X5 4.4i Blue/Tan
'06 E90 330Xi 6MT Sparkling Graphite/Terra
'08 E92 M3 6MT Jerez/Speed Cloth <-- Evil Twin