Yes, the GS and the GTP are a large market looking for an alternative from a big name company like Diablo!
With 5,119 users on regalgs.org and 18,953 users on clubgp.com I am sure there is a built in market for Diablo! Not to mention the many other forums for bonnevilles, Impala's, Monte carlo's etc...........
Another Yes vote here. I'm sure a tuning tool is in my plans a little further down the road, like maybe 2008, so this would be a nice option to be able to compare to the existing DHP and HPT options.