Monitor 4.6 Series 2 tweeter upgrade

I have a pair of Monitor 4.6 series 2 and they sound great. However, I am always looking for easy and somewhat inexpensive upgrades. I have seen online that the RDO-198 tweeters are superior to the SL2500 they have currently.

Can anyone attest to this? If so, how much of an upgrade is it? Is it worth the ~$60 per speaker to upgrade?

Answers