Yes, you can still use plugins in Classipress but not all are guaranteed to work out of the box and will may require further code customization either to the theme or the plugin.
I have checked some threads and there are reported issues when using BBPress with Classipress.
Please help our moderating team work more efficiently by not sending us support questions via PM. You can read more about how AppThemes support works here. However, you can send a PM to follow up and remind me if I missed your support request/thread.
