I had a 2000 and I did put the foam in the frame. It didn't help very much. I also have tried with the bar inserts and the bar snake. All were small improvements, but the bar snake was probably the best of the bunch. The foam in the frame is a pain because it's a pain to clean up the steering stem after you do it. It helped a little, but not worth the hassle.
You might try a RG3 top triple clamp. It has softer rubber than the stock clamp.
I'll bet your best bet before you do any of this might be a set of flex bars. I've never ridden with them, but they might be the ticket.
Also - and I don't know about this - could the jetting affect the amount of vibration? Maybe a few tweaks there would help - and be the cheapest solution.
My 2000 didn't vibrate horribly, but it was annoying. I just bought a set of Tag grips in soft/medium. My friend says they are great, and they feel much softer than any other grips. I got these to help with arm pump, not vibration - but they might be another cheap option for you.