Modifications to Advent baby II

Just wondering what everyone would think about having a set of Advent baby speakers modified with a new crossover , new woofers and tweeters, A friend of mine say he can do the set for me for under $200 dollars, wondering if I should give it a go since I have several pair, personallyI think the baby II SOUND GREAT AS IS, wondering what kind of difference I might notice, or should i jsut refoam the pair and roll with that, and also is there much of a difference in the sound of the babys and the babyII