I think it will be a good fit unless you have sz 15 wafflestompers.. I cant speak for the 2013s, but i have had a 2012 Superstar for 2 years now and i absolutely love it, although I got to say, since i am a III/IV paddler as well, I am really interested in the 2015 4fun for higher water levels.
(i have come to terms with the fact that i am a lowwater playboater, and a highwater riverrunner.Its so much more comfortable for me to be in my superhero in big water.)
Also Because i am at the high end of the weight range, 230lbs now, was 240 last year, I cannot put much extra weight or the boat is too stern heavy. (i am in the habit of always bringing throwbag, pinkit, small 1st aid and H20)
You shouldnt have that problem as much. as far as for down river runs with the superstars. they handle very, very well, but it is still a lil spud of a boat, the potential to get thrashed is always there, but they roll like a champ and are much more stable and friendly then the 2012-13 gen rockstars, for instance. you can pop huge stern squirts and ends pretty much at will, even in minimal current, much less in stong current. I can think of at least 3 friends in your height range or one taller that rock the superstar.
Def initely expect to be aggressive, and maybe a little spooked initially, then you will be super psyched if youre ready for getting after it on the down river play.
I am looking forward to taking my superstar out on the Ark next week, at low flows, whereas it didnt even come off the truck in May, (cause i am seriously a high water playboating weenie)
Plus for reals, we were having a blast running Browns at 1500, Fractions at 2100, and the Taylor at 700ish.... Superhero/Zen/Karma/Remix was all I wanted to be in for (High to me) water....
So yeah, got to really get in it with thin shoes, ( Astral brewers work for me, Or Vivobarefoot running shoes are a great option too) and see how you actually fit, but i would def. go for it.... IMHO you wont regret it.