Correct - thats the determining set of factors, but its really the Vd required at the maximum expected SPL. If this can be accomodated then the driver is fine.

"Any suggestions as to suitable drivers? (The BMS 4550 is known to be a very, very efficient driver that can be crossed very low for instance and outperforms for eg the B&C DE700 acording to some German designers)"

Strange how German designers find German products supperior to Italian ones! For the most part I find the contrary - I like and use B&C compression drivers and I have tested some BMS units that were pretty bad, some are better. But honestly, most drivers are about the same. Take them appart! Do any of them look any different? You can practically interchange the parts. I use B&C because they work as good as much more expensive drivers (like TAD, JBL, etc.) at a fraction of the cost. Why pay for a brand name when there is no perceptable audible improvement?

I am not prone to buy a brand name as I know enough to be able to sort out good from bad, and I can, and have, tested a wide variety of these devices. Simply stated - brand does not buy you quality. Some models of each brand are good and some are not so good. In general, I have found B&C to be the very consistant at a low price - a very good value.

I use the B&C DE25, now the DE250 and I have tested more than a half dozen competitors. Some are comparable in performance, butnot in price, and none are comparable in price/performance, which is why I still use the DE25.