BTC89LS400

So on my 2001 LS430 my Mark Levinson tweeters have finally gone bad, well mainly the front right speaker. Thankfully certain songs sound ok, but there are a handful that make the tweeter crackle and sound poor. It's starting to drive me mad and I also think the tweeters condition is worsening over time.

I've followed the instructions from the HOW TO: LS430 Mark Levinson Tweeter post, but I do not know how to really get to and replace the tweeter unit since they haven't followed up on it...
Has anyone replaced the tweeter units and how so?
(Pic's would be great!)