DTS is a compressed, lossy format, meaning that some of the data is tossed when the music is coverted to DTS. Its analagous to MP3.
DVD-A (in 5.1) is also a compression scheme, but it is lossless, meaning that every bit of the original music is preserved. All things being equal, a 5.1 DVD-A mix should be superior to a DTS mix. That said, DTS (and DD) can sound quite good, but the DVD-A should sound even better.
Back to the question at hand.
If the Sony does NOT do BM on SACD, then the ICBM is easy to recommend.
If the Sony does BM, but it is substandard, then the ICBM is easy to recommend.
But, if the Sony does do a decent job with BM, than you may not notice a big difference, so use the $$$ to buy some SACD's while you still can.
There may or may not be any mention in the manual as to whether or not the Sony does BM on SACD (manufacturers don't like to brag when they can't do something).
I seem to recall that most Sony SACD player reviews I have read seem to suggest that Sony uses a 100 or 120 hertz crossover. That may be workable with your loudspeakers. Without actual SACDtest tones, I am not sure the best way to test this.
Maybe play a SACD that is known to have good bass, but with the sub disconnected. Play the track with the speakers set so that the front L/R are large and the sub is Set to No. Assuming your mains are not mini-monitors, you should have decent bass in that scenario.
Then set the L/R to small and set the Sub to Yes (but leave the sub disconnected). Is there a noticeble difference in bass? Did it drop off of the map? If so, then at the very least we can conclude that the Sony does BM on SACD. Plug the sub back in, and play the track one more time. Your low end should be back.
But, If there is no difference between test 1 and 2, then it probably does not do BM for SACD, and your next step is a call to 1-800-Outlaw.
Brian