My friend you have done an enormous job ! As i am a S 45 user (which i bought as rubish and had spent one month o repair) sound is excellent. S45 has a volume of 25 litres ang S55 has a volume of 32 litres which might change low frequency sounds.On the other hand it can sound good why not?. On my S 45's back part there are 2 air windows can be opened

Dont worry Mr Aultman, The S75 speakers does not have a constant Ohm value due to the crossover units built inside,you can easily see it from ( they range from 4 to 8 Ohm according to music load) http://www.beoworld.org/prod_details.asp?pid=671