Wayne,
The Turbo 2 was the name used to refer to the original 964 Turbo released in 1991 to distinguish it from the pre-964 Turbos (of 3.0 and 3.3 litre varieties). The 964 Turbo used the same engine carried over from the pre-964 3.3 litre turbo car until the release of the Turbo 3.6 (it's correct name) in 1993.
In terms of numbers there were around 5300 Turbo 2s produced (approx 3000 ROW, 2300 USA) for the 2 model years 1991 and 1992. By comparison only 1875 Turbo 3.6s were produced for 1993 and 1994 (approx 1100 for ROW, 750-ish for USA). As you can appreciate, the 3.6 is a much rarer car and justifies a significantly higher price. Don't confuse the plural "s" above for the "Turbo S" models which are a completely different kettle of fish!!!
Regards
Dave