with Carista, you can create a backup of the current settings and use that to restore if you are concerned about not passing anything.
you are installing an odb2 reader, just like they would if you went to an auto part store. its temporary and you are not going to install anything permanently or void anything. just create the restore file and you can use that if there are any issues.
yes its a subscription, but you also get a free month and can also get it for a monthly fee if you ever want to change it back.
trust me you are fine, you will pass everything and if you don't want to chance it you can always change it back