Hello Jeramias, I didn't, then at 150K, it didn't have the power to pull up Balmoral Ridge range, plus the fuel economy went to dishonorable lows. I had the timing chains and sprockets replaced, and it gets up the range without problem. So perhaps the answer is no to being required to change them at 100k, you will likely have steady decrease in performance and economy. I am told that when the chains get sloppy, engine damage can occur. The whole job cost me around $1400, plus I purchased the kit with chains sprockets, tensioners etc...
ebay timing chain set kit
I had a Commodore VZ that developed the same timing chain issue, but the engine got trashed. So changing them seems advisable. The improvement in economy will help pay the bill, and daughter gets to use the handicap seat lift, instead of the Phil-Lift....Phil