reviving an old thread here but i figure some people may be interested in such things.
Start by clicking "User CP" in the top left corner.
Under "Settings & Options" Click "Edit Options"
Scroll down to "Thread Display Options"
Change setting "Number of Posts to Show Per Page" to "Show 40 posts per page"
Go to the thread you wish to save and start at page 1
Click on "File"
Click "Save page as..." (or press CTRL+S)
Choose the location you'd like to save the page, title the page appropriately
in the "Save as type" drop down, select "Web Page, Complete"
Repeat the steps for each page of the thread, saving them in the same folder
this saves all code. and all images. at this point the only thing that will require modification is the link tags for the page numbers, previous page, and next page. The easiest way to handle this is to open the file in notepad and find the code for the links you wish to change. If you titled each page simply with a number, this will be very easy. in the link tag change the href attribute to the corresponding page within the folder.
Example.
Open the GT12 thread to page one, save it, make a new folder labeled "GT12" save the page as "1.htm", continue until you have saved all 83. starting with page one open each of them and find the tags for the page number and next/previous links. on page one change the href attribute for page two and "next" to read href="2.htm" so on and so forth for the actual page number links. do this for each page and you will have a complete duplicate copy of the thread in its entirety.
It is a little time consuming but i find it to be the most thorough method of saving threads. If you have good working knowledge of html this will be a very easy, if you don't, try finding a wysiwyg web editor to aid you in modifying links and such.