Surely all the complaining Wren 160 customers have just been unlucky. Wren clearly state in the advertising blurb for the new Wren 180, that the 160 was highly successful.
" Additionally, we took the opportunity to enhance the performance and reduce the overall weight but without sacrificing any of the standard Wren quality customers have known and expected. The result was the highly successful Wren 160, launched in Dec 2008".