White Vega and Maxxiss blue and pink. I bought them used. I am pretty sure they used Krug on the outside but I don't know about the inside. I will try to find out. They still have good rubber and edges look good. I don't think they were ran that much.
I may buy one new set. I don't know what to go with. Will post what I find out. Thanks
Krug is considered a harsh prep. Anything with goat in it is harsh as well. This tire will probably only be good for tracks that take a harsh prep at this point.
Now, as far as compatibility between certain preps -- that's a toss-up. I am most familiar with our own prep line and know that our Black Bite 2.0 does not do well with Krug already in a tire...it will work, but stays greasy too long for most applications (especially if used trackside.)
Prep changes the molecular make up of said tire, you can not undo those changes, You can alter the changes by using another/more prep.
The compatibility of some preps do not work well, others are no issue.