Headers and fulltime to parttime conversion..

[MacMek20]

Hello,
I have a couple of questions on some things.
First, headers. Right now I have full length headers, not sure who they are made by. Just a week ago, they rusted through enough so that there is a hole in them. Right now I don't have much money, so I am looking for a cheap set of headers. I saw a set on SummitRacing for $100 and was thinking about getting them, would they last through winter? Would they be bolt-on, since I already have full length headers installed?
Link: http://www.summitracing.com/parts/SUM-G9006/
I noticed that the flow-tech headers that they also sell appear to be the same thing, but cost more.
I was also considering installing the Mile-Marker 501 kit in my np203 transfer case so my truck isn't full-time 4wd. Would it be worth my time? I don't plan on putting huge tires on my truck (max I would even consider putting on it is 33"s)
My truck has a 350 and auto tranny.
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