[Coco] DriveWire 4 'Turbo' ROM for CoCo 1??

[Chad H]

I was about to work on flashing a ROM for someone that has a CoCo 1 and they
are interested in both the standard DW3 ROM (which I found in the archive at
http://toolshed.sourceforge.net/snapshots/) as well as the 'Turbo' version,
which didn't seem to exist in the ZIP.  I do recall something about the
serial hardware of the CoCo's having different speed limitations.  Is the
CoCo 1's serial not fast enough to support the Turbo mode?