I strongly advise having guages if you are going to install a chip. Especially if you aren't going to go with straight exhaust and an intake. If nothing else, at least open up your exhaust so that heat can escape. I have an intake on mine and believe that it helped tremendously. It allowed much better air flow, and cut down on the black smoke, and in your case, towing a trailer, you aren't going to want it to be black by the time you get where you are going
When you are pulling something, those EGT's can climb really really fast, and you want to be able to keep an eye on your tranny temp too... Just my two cents on this one, but I think the other guys will agree