I am in Changi right now, having arrived at 1.30 AM. The transit hotel in T3 was full, so I recommend booking in advance if your stay is critical. There is also one in T2 but I did not check it. Since I had slept very well on the flight (those flat beds are awesome!), I went to the Silverkris lounge and took a shower. Note that there are only showers in the Business lounge; if you are in economy and *G you have to go to the Gold lounge which does not have showers. But there are for-pay showers on the same level if needed. I did not see any lie-down chairs in the business lounge, but there was a "resting lounge" nearby for all passengers with reclining seats. Now I am having breakfast in the lounge and will soon head out to Singapore for some shopping and sightseeing!