Hi Ken, I understand that in normal circumstances, in a single driver, non tuned enclosure the TheilleSmall parameters are not too important, unfortunatly due to this being a multi-driver, tuned enclosure, and Bose to boot, the drivers specific parameters are very very important. the unit is 1 ohm for a start, it works in a series parallel combination with 7 other drivers and a directivity control circuit wired between certain drivers in the matrix. So in this case I do need an exact replacement, hence the cost they are asking.
Jon