The mazda 6 and the dodge stratus, both from pro line are good shells i have used both. The mazda probably has a bit more steering than the dodge but the dodge feels more stable at higher speeds and cornering IMO
The DNA3.0 apparently is a good shell that a lot of electric guys use, i've never seen a DNA on a nitro car before but that's not to say there aren't any. Not sure what they are like performance wise.
Another good one that a lot of people are using here in OZ with great results is the Team Titan Blitz Altis 2.0. Looks to me like an all round performer
Hope this helps