Chains are due then mate. I thought that when I bought mine, having chains would be better. After some research it turns out that VX say every 100K to change them. Early ones had issues with oil feed to chains and then main chain tensioner. The latest kit uses the tensioner from the NET engine I believe which is better. Early tensioners had a habit of getting stuck in a compressed position thus loosing all tension on the chain and the likelyhood it would jump a few teeth (or even potentially snap). I would get it looked at as soon as possible, to see whether the chain has jumped a couple of teeth. Sounds like you have an idea it has by your first post with rough idling etc. I would think that your balance chain will be shot as well if the main one is stretched. My main chain was okay when @[deleted] did mine but the balance one was shot (was just starting to clip the casing). What engine is it, Z22SE or Z22YH?
The best part is your in the best place for advice mate.