I know what you mean by monsoon.... I was in Edgewater driving home from the supermarket in torrential rains this evening. Many of the roads were flooded. Luckily, I was in my A4 Quattro instead of the Boxster.
I think the part you are posting is item number 6 here:
http://www.pelicanparts.com/PartsLookup/HTML/986_USA_KATALOG/501-01-Frame3.htm
It's listed as a rear axle bracket.