Adding grapes to wine kit?

I have been thinking of making a red wine from a wine kit. I also have some grape vines which produce wine grapes at home. The problem is..they are several different grape vine varieties growing together...all of which I am not sure what they are. I have both reds and whites, and not enough to make a batch using just the grapes themselves.
So I was thinking. I have heard the addition of grape skins to concentrate kits adds complexity...but these skins are normally supplied by homebrew supply stores. I on the other hand would be adding a small amont of mystery grape skins to a specific style of kit concentrate. Would this be beneficial or harmful to my wine. I am thinking several things can happen. 1. added complexity without altering the style of the original concentrate. 2. added complexity with changed style. 3. Contamination. 4. No added complexity.

Anyone have any thoughts?

The grapes would alter the flavor profile, depending upon how many grapes you use, the kit and the grape variety. It might be better to try the kit as is and use the grapes in conjunction with a country style wine like blackberry - especially given the fact that you don't know which varieties you have. Raisins are good, safe additions to wine kits.

With fresh grapes, you'd want to crush them and add the proper amount of potassium metabisulfite to fix, or set, the color and to kill any unwanted wild yeasts. Another thing to consider when using fresh grapes is the possibility of a secondary, or malolactic, fermentation which would be detrimental to a kit.