I wanted to point out one difficulty I found when archiving some threads. The archive format does not preserve the bbcode, specifically quotes. I'm not sure how the threads you are referencing are formatted, but if there are many quotes it becomes nearly impossible to read. The quoted's sentences run right into the quoter's, etc. I couldn't tell where my sentences began and the other guy's ended.

I did have luck saving threads as PDF, though. I found a handy Firefox Addon, the cleverly named "Print pages to Pdf" , that lets you print every open tab into a PDF document. It may be a tad unwieldy, but you can open a tab for each page and then use the addon. I archived a thread this way with 10 pages per PDF and compressed a thread into 8 pages, but there's no reason you couldn't do it in a single pdf.