I see that in a comment on the AWR Dilemma that Alex Gorbachev has pointed out the existence of the parameter _awr_restrict_mode as a possible attack on disabling AWR.
For a few more options to disable the monitoring overheads of 10g when you aren’t licensed to use the diagnostic and performance packs, you might also want to investigate the effect of the following parameters – quoted here with their descriptions from x$ksppi.
_addm_auto_enable governs whether ADDM gets run automatically after every AWR snapshot _ash_enable To enable or disable Active Session sampling and flushing _ash_disk_write_enable To enable or disable Active Session History flushing _swrf_mmon_flush Enable/disable SWRF MMON FLushing _swrf_mmon_metrics Enable/disable SWRF MMON Metrics Collection
There are several more related parameters but the selection above appears to enough to eliminate ASH, AWR, and ADDM.
As always, you need to remember that you should not set hidden parameters on production systems without approval from Oracle support. Note especially, I have only run a couple of small tests on the effects of these parameters – so I haven’t looked for any side-effects to changing their defaults.