Reading up on Norton at their site would be a good idea, as Kyn has provided the link to do so.
If y'er still concerned with it, just soft thorough the comments on DA and see if anyone has mentioned anything about viruses or other bad occurrences when downloading the ENB. If they're all positive, I think 'tis safe to say that ye can download it without worry.
To be honest, I think I may download this m'self! Thankies f'er sharing the link. If ye'd like, I'm willing to be the Guinea pig and test it on m'own computer as let ye know what happens.