I read this on Alpinecarving.com about the Madd 158, although it wasn't specified as a BX board:
The 158 cm length (8.8 M radius) board requires an advanced weight-forward technique and is not suitable for beginners. It is also necessary to maintain a more precisely balanced center of mass to get the optimal edge hold characteristics. It offers the unusual combination of small sidecut radius and high stability, which is great for narrow runs. The very tight 8.8M sidecut allows you to put your twitch muscle to work. The 158 also proves one corollary: the length of a board does not necessarily matter. The Madd 158 is like a German Sheppard: if no one is in charge, then it will insist on being the one in charge.
Does this pretty much describe your board?
I also read this about the bases:
'Old models were made with a highly durable graphite base. Later models used a double sintered p-tex 4000 speckled base. Some carvers have remarked that the older base didn't hold wax as well'.
Can you tell me which base it has?
Thanks!