got turned down for an alignment

[Marco Canta]

  I just got turned down by a local auto shop for an
alignment because he says the center thingy on the
alignment rack will hit my Stillen GTR bumper of my
recently lowered car.  Is this a common problem?  He
says to come back with my bumper off,  but I notice
that parts of my car are lower than the bumper.  Will
not those hit too?  I've never heard of this
problem....you think Pep boys or Meineke will say the
same thing?

Thanks,
Marco