No. EQ Pixie does not access EQ memory or intercept any EQ communications. It does not "modify the Software [EverQuest] to change Game play." It does not provide macros or scripting. Don't let that fool you; it's still very powerful. EQ Pixie primarily works by using features that were built into EQ for users to access, but which few can make use of because you need various computer skills or time to do so. For further information see the EverQuest End User License Agreement, particularly section 9.

Yes. You may install EQ Pixie on as many PCs as you use. However, there is a limit to how many times a single account can be logged in at the same time.

Generally, if you can run EverQuest, you can run EQ Pixie. Most people will not see any change in performance because EQ Pixie takes very little resources, especially compared to EverQuest. Only those who can barely run EverQuest in the first place may see a difference, and even then changing some of the EQ Pixie options should help (try disabling alerts). The best way to be sure is to give EQ Pixie a 2 week free trial. There is no obligation.

It currently only works with servers that use English game text. Some features will work anyway, but most features depend on parsing the EQ log file and will only recognize phrases in English.

I often answer questions by updating the Manual. You may want to check there. It is easy to navigate since it has a table of contents. Also note that there is a Subscription FAQ.