In the day's of yore, bi-amping was common. True bi-amping would mean a separate and dedicated amplifier for the lower bass frequencies and another for the tweeters and mids. The tweeter's and mids use much less power than the woofers to produce similar perceived volume levels. When you order the bi-amp option there is a connector between the 2 sets of speaker posts , these are removed when you are bi-amping , thus nothing is needed to be done to the crossover as it has already had the Mid/tweets separated from the bass portion of the crossover. These days most people use a subwoofer with a dedicated amp , and as such the requirement put on your main amp is much relieved , making bi-amping pointless and expensive. The guys out there who say interconnects and speaker wire make a difference are going to disagree with this position, so I guess what matters is which camp you are in.
As for cast baskets, Ian has done extensive testing and has proven to his satisfaction that cast baskets are not necessary and are eye candy. I personally believe that small drivers do not benefit from cast baskets but large bass drives do. I think there may be a small advantage in heat dissipation but have no way to prove it. All my car audio subs that I buy have cast baskets based on my preference'.
