Unless we all misunderstand what comes in the GT package and you must have the GT badging, I think it is actually cheaper to buy an MTS Touring and add the accessories. Here's the math list to list on a 2013 using Pro Italia's online retail pricing for Ducati Accssories: (Tax, tags and fees extra)
'13 MTS Touring: 19995.00 (includes standard panniers, obviously)
Top Case: 658.00
73L Pan. Covers: 350.00
DP Crash Bars: 353.00
Supplementary Lights: (?) 300 (just guessin')
'13 MTS GT: @21995.00
Did I miss anything?
And, you have both sets of pannier covers buying it that way (as a "T" and ordering the bits separately). I didn't include any difference in case there's a "better" screen on the GT but if there is, that leaves over $300 to buy it
Unless there's a lot more to the package than we know of now, you are better off buying an S Touring and putting the stuff on yourself. Top box and crash bars are an easy job for anybody with eight fingers and two thumbs, hardly worth $650 to have "factory mounted." The supplementary lights are the one wild card. I priced lights at $300. Do you even need them? Who knows?
You're good, Turkish Express! Unless I missed a major component, (always a possibility!) the GT package doesn't seem like that important an option set to me.