Towing 3500 lb Car w/ 1500 lb Trailex - Bad Idea?

I think you should be fine. I have a 2011 regular cab base 4x4 with an I4 and manual gearbox and I tow a 3500lbs trailer daily (which is its max capacity according to the trucks specs) and twice a year I tow our 6000lbs boat to and from barkers island in superior WI to Piedmont Heights in Duluth MN. The daily towing is not really an issue and I feel totaly ok running it to its max capacity for it handles the trailer well even on steep inclines. Towing the 6000lbs boat is difficult and I always have to use low speeds, low gears and high rpms, but for twice a year, i figure its ok. Only thing is my mpg's go down to around 14-15.

So long answer to your question, I think if my I4 can do 6000lbs every once and a while and 3500lbs daily, i'm sure your V6 will be more then capable.

Hope this helps