Of course there is some carry over in parts. The steering wheel is sort of the same in other SRT products. The gauge cluster has shared elements, and so does the infotainment system. But, you really can't expect those big budget items to be built custom for the Viper.
But, beyond that - there is nothing in common with the RAM or Dart. I test drove a Ram 3500 last year and it wasn't all that impressive inside.
Finally sitting in a 2013 Viper (Both a GTS and SRT), I don't really see how you could compare them to anything else offered by dodge. IMO, the interior is superior to almost anything I've ever driven or been in. It really is just beautiful and refined inside. IMO it is getting up there to the "Ferrari" level (though I don't think it is there). It runs right over what I've seen from BMW and Mercedes.
As far as price, lets not forget that though 2008 isn't that long ago, $95k today is the equivalent of $89k in 2008. So, going from the SRT10 to the base SRT now, you see an increase of $5k. It is a bit disingenuous to compare a fully optioned vehicle to the previous generations. To boot, the only real mechanical differences in the SRT and GTS are the shocks, the rest is window dressing.
But, I do agree mechanically this is more of a .5 iteration of the Gen IV, but interior wise it is absolutely a new generation.