Removal of Optimus/Lineaum dipole tweeters

La45 is correct from what I know.
If I were really concerned, I would get some dampening sheets and coat the entire inside of the speakers...

There are plugs under the grill that need pulled out to get to the screws. The woofers then remove easily. Madisound has lots of threads on upgrading the crossovers and woofers. I replaced my woofers with Vifa 4" and it made a very nice difference. Some better insulation helps too. Crossover is simple and seems best if left alone.
I've seen people use the tweeters as super tweeters (ie old planer speakers without tweeters or with Lowther types). This doesn't require much of a crossover, just resistors to limit low frequencies from burning out the tweeters.