Petsc 3.5.2 (update)

Update PETSc to the newest version.
Add numerous dependencies (metis, parmetis, scalapack, mumps, superlu_dist)
and options (compex/real).
that's what is written in the PETSc website http://www.mcs.anl.gov/petsc/documentation/installation.html:

"It's best to install some external packages like SuperLU_DIST, MUMPS, Hypre, METIS, and ParMETIS with the option --download-PACKAGENAME. [the correct options for these packages are --download-superlu_dist --download-mumps --download-hypre]
This will install the COMPATIBLE version of the external package. A generic install of this package might not be compatible with PETSc [perhaps due to version differences - or perhaps due to the requirement of additional patches for it to work with PETSc]
Some packages have bug fixes, portability patches, and upgrades for dependent packages that have not yet been included in an upstream release.
All packages will be installed with the same set of compilers - this avoids problems [for example weird link time errors] with mixing code compiled with multiple compilers [for example mixing gfortran and ifort compiled code]."

so i would keep this option.