You can make use of pneumatics with or without the compressor on your robot, although if you do not use it, you must have wiring as though it is on the robot. If you put the compressor on your robot yes, it's part of the weight total. If you don't put the compressor on your robot it doesn't count towards your weight.
As for the Q&A part, are you attempting posting in the "Ask a question" subforum? It took me a few minutes to figure that out.
