Great thread. I wish I had seen this earlier!
I modded my 600D more than a year ago. Things were ok except for two things. One, some dust (at least one of them too big to ignore) got in and was annoying. Two, there was some focus shift - the sensor assembly was not sitting square - because I was not careful enough in marking the screw positions/measuring the aount of shift.
Couple of days ago i wanted to remove the assembly again and try to clean the BCF filter. That's when I realised that there was a third mistake as well. The silicon glue was clinging on to the LPF-1 and it refused to come out. I tried to coax it with all the delicate handling I could manage but it eventually cracked. Now, I have no way of getting a replacement of LPF-1 since the Canon service folks here say it is not available as a replacement part. Now, I want to remove the BCF filter as well and make it a full mod. I am getting the CLS-CCD filter from Astronomik and it should be arriving before this weekend. From what I understand from this thread with the bare CMOS sensor and CLS-CCD filter I am good to go assuming that I always leave the CLS-CCD in place. Requesting the gurus here to confirm my understanding.
Also, just in case I want to shoot without the CLS-CCD will the problem of star bloat be noticeable? Of course, I can figure it out when the clouds clear (it looks like it will be at least another month before I get to see some stars here!) and just wanted to hear from the sages while I wait for the clouds to clear. If it makes sense to leave the BCF in place I can do it now rather than open the camera when the stars are out finally