According to a recent article in Apple’s KnowledgeBase:
Logic Pro 8 allows you to utilize the processing power of additional computers (nodes) on a Gigabit ethernet network. Most of the plug-ins native to Logic, and many third party Audio Unit plug-ins, can be processed by node computers.
You must install third party and DSP powered plug-ins on all node computers and the main computer. This means that all nodes need the physical hardware required to run the plug-ins. For example, to run Universal Audio (UAD) powered plug-ins from a node, the master computer needs a UAD card and each node connected to the master needs a UAD card. However, there is no practical advantage to running DSP powered plug-ins on nodes. Any DSP powered plug-in assigned to a node computer will also be opened from the main computer, so there is no net gain in power.