How stiff is the TNK?

SO with the student discount that 4frnt is offering its looking like I need to get some of their skis. I need a park ski.. mostly for rails and jumps, never really ride pipe 2 much. leaning towards the TNK because I like the 89 underfoot and its almost semetrical. the thing is i want to be able to butter and press and im not sure if this is going to be possible if i got the tnk. the stl is 84 underfoot and i hear its more flexy. can anyone comment or help me out with this. thanks