I think only the A8 (large) model is in stock and can't predict the future as far as availability goes for sprungs. For those that already own the chassis or can find them used they could put them on this boot - otherwise someone would have to choose another option for a chassis. The point is a person can put whatever chassis they choose on the skates without having to first remove an ice holder. Weight isn't everything. Fit, durability, overall performance and other attributes all play a part, but if you can save some weight on anything that goes on your extremities without sacrificing fit or too much durability then that's a good thing. Sometimes people are a little too hung up on weight though - it's better to have skates that are 100 grams heavier that fit you well then lighter skates that don't fit properly ect. and I don't think most people will notice the difference of 100g or less in practice.