Thank you for contacting Samsung. Those weights of paper are beyond what we recommend for this unit. You can do up to 59 lb bond multi-purpose tray, but beyond that isn't recommended. Thank you for being a Samsung customer!
Is the hard drive only used to spool jobs, or are there instances/requirements where one must have a hard drive installed; ie printing pdf files directly to printer etc.? If there are cases where one is required, please elaborate as to why.