The T9 shifter comes up in essentially the stock location on any of the cars that came with overdrive and the shifter in the rear location, 123 GT, 1800, etc.
( and yes I know that there are two different lengths, early and late )
We have had to modify the tunnels on cars ( 544 definitely ) when installing the M41, but I don't remember having to do that with the T9 ( the extension on the T9 is narrower than the M41 overdrive unit), but do also do not claim to know every tunnel variation on each of the models and model years. My recollection is that there is an actual part to modify the tunnel for the rear M40/M41 shifter location on the 122, and someone told me quite recently that it was still available.

One issue on the T9, at least with the adapter setups that we have used, is that the bell housing has to be bolted to the trans before it is installed. This can make installation a little more difficult that just installing a trans with the bell housing already bolted to the engine.

John
V-performance.com