Here are several bugs, and one of them is critical. These bugs I have sent to support and they have acknowledge their existence. I will just broadly list the bugs without going into details how and why. If there is interest here, I will be glad to post exact details.
1. CRITICAL BUG. Adding kit items using UPDATE command. It is not working, and not only that if you run it will WIPE all kit items from the database. Be careful.
2. Shipping data. Node that takes care about shipping information is not working. No danger here, but it just does not work.
Unfortunately, I do not have source code where I could fix it myself
Hope it might save someone from hours of hair ripping.