Having neighbour troubles as well, I too dream of doing certain things, but need to reinforce that many suggestions here will land you in the proverbial.
Can I suggest something of a very effective nature, and perhaps something enjoyable if you give it a chance ?
Get yourself a classical instrument. Rent one maybe ? Something loud though (Violin with amp ?)
Learn to play it to a rudimentary standard (that is the bit you might enjoy - who knows ?!)
If possible, find out what he plays through the speakers.
Learn that music to a rudimentary standard.
When he starts up you start up, but make sure you are ahead, or behind the timing.
If you play close enough to the speakers, the phase difference will drive him absolutely nuts in a short period of time, e.g. think bagpipes that are out of tune.
An easier thing to do would be, as simple as it sounds, shun the person. That is, whenever you or anyone else in your house sees him looking over your way, turn your back to them. It can be a powerful psychological tool without saying anything nasty, doing anything nasty, or putting yourself at any other risk of trouble.
( All this spoken from someone who has had a mentally unstable neighbour that was indeed dangerous and you couldn't provoke him let me tell you )
Hopefully all has been going well since the last post though