I have done a couple of modifications to my 15-22s, and have created a bit of a "how-to" on Flickr.
The are three photo sets at present:
1. Modifying the existing safety to an ambidextrous safety.
2. Pinning the 25 round magazine to 10 rounds (required in Canada).
3. Modifying the handguard and related items.
I would appreciate it (if anyone is interested) if you could take a look and comment prior to me putting together a more detailed version.
My Flickr account is MWL13.
Regards.
Mark