Well, Apple claims that the HS SCSI card is about 2 or 3 times faster than their old SCSI card for some applications. Though I have never tested the original card to see how credible that claim is.

The error that Unknown_K is talking about is trivial, and I don't understand why he makes a huge fuss about it. But he does. } Simply put, if the HS SCSI card does not find a bootable device it will display an error message. You just break out of that error message and type PR#5 to boot from the 3.5" drive or PR#6 to boot from the 5.25" drive, and floppy based software will boot. If you think that is crude, you can use the Taifun boot manager (if you like keeping the hard drive powered up) or simply ensure that the GS searches the SCSI card for bootable devices after it checks the floppy drives for bootable diskettes.

As per memory, the ROM03 has 1 MB onboard and the memory card supports a maximum of 1 MB. So 2 MB sounds right. A 4 MB card will get you further, but will cost more money. A 8 MB card is almost pointless. They were never that common so most software just doesn't need it. (I was told that they are uncommon because they were hard to design, and of course more RAM means more $$$.)

The composite may be greyscale only. I don't know, as I've never had to use it.