Some stages I get are rars, shouldn't they be pac files?

[Bossk]

Do I install it as normal or... what?

[Sylv]

You have to open it with an archive opener, I suggest using 7-Zip. Once you download it use it to open the downloaded file and the necessary files you need to add it should be in there

[windhunter7]

.rar is the extension of a zipped folder; it's the equivalent of a .zip file, where you can right-click it and click "Extract here"; I would suggest either winrar or 7-zip to extract it.

[Bossk]

I got it guys. Thanks for the help.

[StefanDeFranco]

I cant run the alternate stages except the stages of the normal PM?