Actually I'd set the max output on the Bricasti at 10dBm or 2.45V to make sure the 1160 wont clip or even at the minimum allowed of 8dBm to have 2dB headroom left on the 1160.
You just have to see if you can get the SPL you want especially with audiophile recordings that have a lower RMS level.
The Bricasti has trim pots on the back to raise or lower the output voltage on the XLR outputs between 8dBm (1.95V) and 23dBm (10.95V), which you can use if you find you can't reach your desired SPL (see the Analog Output Sections at p.3 in the manual).
Bear in mind that the 1160 has a gain of...
It depends on what you are after. A preamp can add some distortion that can be subjectively pleasing, while driving the amp direct will always be more transparent to the recording.
I'd say, if you value transparency, if you like the sound of your DAC and if you can have a proper gain staging...
If you listen only to digital sources I'd stay with the Bricasti DAC direct into the Boulder as it has a powerful enough output stage to drive it without problems (check the manual if you need to set a higher output level).
If you also have a phonostage and need a preamp I'd try some more...
It's true, nothing comes quite close to the Burmester chrome mirror finish, looks great.
If aesthetics are important to you I'd also check the Accuphase C-3850, very refined looking with its champagne color and polished red wood case; from what I can see in your profile pic would blend well...
Would have been interesting to also try the P3000HV and the 077 (if the dealer had one) preamps with the 909mk5 amp; I think the loss of details and imaging precision was due to the 808 preamp.
I bet the distortion is higher in bridged mode than in stereo when driving 4 Ohm loads or lower; just because they work with such loads doesn't mean is ok to do it. And there's no way a 911 could give 1.2kW @ 2 Ohm when the amp only has a 750VA transformer.
There's a reason for the 909...
I think the problem is the 911s are not really fit to drive bridged the 800D difficult load so they sound worse than single stereo (you should never bridge amps to drive 4 Ohm loads or lower). Are both amps MK3 versions? Since you bought them used I'd send them to Burmester for a checkout and...