325-350 is not a problem. I currently have a Stumps Platinum 5 and before that, I had a Stumps GF223 (that would be the classic today). I had my GF223 over 500 degrees.
Any of the cookers mentioned will do a fine job for you. I would check out all 3 and see which one you think suits your needs the best.
Eagle River Barbecue
Stumps Platinum 5 Trailer
Members Mark 8 Burner Gasser