Yes, the E will feel stiffer than your C's, and yes, the larger tire will feel more sluggish no matter C or E (worse with E). Your mileage will decrease 1-2MPG.
I have E 285/16 Duratracs and pretty happy with them. I haven't had C rated tires to compare though.
'98, 5Speed, 3.4, 33's, 17ish...