I helped a buddy modify his air system similar to what you described. All things being equal, you should be right, but, in my buddies case, EGTs were INCREASED. We knew this of course because of the use of gauges. So one cannot assume the results.
We actually designed a plenum that looked really funny, but helped EGTs down about 75-100 degrees from the original baseline.
Any mod can obviously be a double edge sword, but it is good to quantify results.
BTW, I don't tow trailers or do anything crazy either. I can tell you that the boost and EGT gauges came in handy when one of my intercooler boots popped and I didn't realize it.
To each thier own.
Dave