I did notice the high reccomended cutoff of the B&C as well. I checked out the two P.Audio drivers you mention, the PA-D45 looks nice, with reccomend 1K xover freq. I am using the Pi Crossover, at either 800Hz or 1.6KHz (have not decided yet). I'm thinking that the PA-D45 is designed for PA use (hence the model number!) so it may sound like crap for Hi-Fi purposes? I did also look at the BM-D450, it looks nice too, but reccomened xover of 2.2K and freq range of 1.5K to 20KHz :( What do you think of the P.Audio SD line? The SD-450 N has fs=750Hz, and freq range of 500-20KHz. The freq response graph can be seen below:

http://www.paudio-europe.com/products/db_product.htm?v_tipo=2&v_tipo_desc=DRIVERS&v_num_series=13&v_des_series=SD-SERIES&v_id_art=284

I am not sure what horn this is measured on though. Maybe you can just let me know if you think its a worthwhile driver?

Oh ya, do you think titanium is the best for the diaphram?

Thanks for your help so far! Adrian