If you are in a situation where a prosecutor is pointing the finger at you in court, he is likely to use every trick he can to make you look bad. If you look at the Larry Hickey case, they used the fact that he had extensive firearms training to try and make him look like a paranoid nutjob itching for a chance to shoot someone, rather than look at him as someone who went the extra mile to be responsible and learn how to exercise his responsibility - and that was in Arizona.
So I think it is possible a trigger modification could come up as an issue if you go to court. However, as others have pointed out, there are very good reasons to use the NY1 spring. As long as you can present a good coherent explanation for why the trigger was modified and how it increased your safety or control of the weapon, I think you'd be in good shape. Having the work done by a Glock-certified armorer certainly wouldn't hurt either.