
I thought this was a great shot via
this VSE thread. I used to think the same, however some mods can actually be good, very good. Below are a few more mods from the thread. If you click on the DIY label you will see hundreds if not thousands of DIY posts, some including mods.

The mods pictured here:
Patch points
The
Alesis Aurora
Rhodes Chroma with the
CC+ Process Upgrade that adds full MIDI, and cosmetic improvements

Note the thread was originally on the rare Roland SH-3 vs. the newer SH-3A. Word is that Roland had to change the filter design on the SH-3 as it was too close to Moog's ladder filter. You can find some mp3s in the thread while it's up.
Update via Hajo on the SH3 rumors:
"My first Synth in 1976 was the Roland SH3a. I know all the stories about the differenes between the SH3 and the SH3a. So somebody talked in the WEB that a SH3 has gone for a huge amount of money (something like 12.000 US$) an VEMIA. In my opinion this is a hoax! I talked to Roland tech-men in Germany. He told me: There is a difference between the SH3 and the SH3a. The difference is only the design of the board internal. Some parts are arranged in a different way to improve the layout of the board. There was never a Moog Filter inside!!!"