Greesemonkey/User Scripts for Opera
Go to Preferences>advanced>content>javascriptoptions and set the folder where you want all your scripts or you can set it to be page specific by right clicking on a page and edit site preference>scripting.
Below is a link to a script simular to Firefox Grab and Drag extension. (Scroller.js) open the script with notepad to edit it. For example to get rid of having to push ctrl to activate it. Set it to “false” (outstanding script)
Scroller.js
Too many scripts will slow down Opera.
Adblock for Opera
You have to create a uri.filter file and put it in the install directory. In the address bar type opera:config and type URL filter and specify the location of the file. Of course you have to create the file with help from the link below.
Make Firefox Addons compatible with your current version.
First you have to modify install.rdf file. Download the extension without installing it and open with 7zip or other. Open install.rdf with notepad and find the following line. <em:maxVersion>2.0.0.*</em:maxVersion>
Change the it to <em:maxVersion>3.0.0.*</em:maxVersion> to make it compatible with FF 3.0 and above. Save the file and install extension by draging it to the addons window in Firefox. You may have to extract the xpi file (extension file), edit the rdf file and then drag it into the original xpi or maybe recompress into an xpi file.

