Maybe your over thinking it all.This design has been used by all the manufacturers incl caterham ,westfield,dax etc. I think if there was a problem with the design one of the large manufacturers ( caterham etc)would have modified it and everyone else would have followed suit.Also remember that the roadster chassis has been design on cad and tested for stress etc.
Maybe you just need to slow down over speed bumps
Just my 2p worth