Without knowing exactly how you've modded your version of Kursk I can only make general comments, but knowing the following may be of some help.
Installing any HPS or JTG patch will always restore a certain amount of the original art, which in almost every case is a very bad thing, though the problem is only an aesthetic one.
The only time a mod will interfere with a patch is when it contains some kind of working file with an identical name to something included in the patch.
The only major mod that does anything like this is Volcano Man's, but he was careful not to use the same names for his files. That's why you'll hear people talking about _alt scenario's. Even though there are some fundamental differences between a plain vanilla and an _alt scenario, the _alt's are tied to the McNamara database, which doesn't overwrite anything in the patch.
Bottom line: Volcano Man's mods can be installed over a newly patched HPS version without any bad effects.
If you add things to the inside of the game folder that doesn't overwrite anything, it won't have any impact on the patch. How you get it to show up in the game is another matter entirely.
Last time I looked Jison's mods only change graphic images, so you can add his mods at will. His mods work best if installed over a newly patched HPS version that already has the latest Volcano Man mod installed.
My mods also make a few non-graphic changes. Last time I looked all of these were to sound files. Most of these are really just the inclusion of weapons sounds from the other games that keep getting left out of the patches for one reason or another. I do include some night background sounds that weren't there before but which the newer versions of the HPS game engines will play when appropriate. And some of my mods include victory music that wasn't written by an afficionado of American Muzak. But none of this will interfere with the integrity of the patch.
These three sets of mods assume, and in some cases depend, on your using the most recently patched version of the game. There are other mods out there that I'm not all that familiar with, but a few of them probably do use files that will overwrite a patch. Once again, the basic rule of thumb is that graphics files can be overwritten ad libidem without messing with the patch. Applications, oob's, scenario files, and things like that probably aren't a problem as long as they don't overwrite anything. The problem comes when you use a mod where the designer didn't create scenarios with different names or (even worse) created specialized oob's that use the same names as the vanilla versions.
For a complete set of links to the various mods that I've mentioned, take a look at some of the threads in the Panzer Campaigns section of the HPS part of the Wargamer website.
http://www.wargamer.com/forums/tt.aspx?forumid=211
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