Please be aware that Kuala Lumpur and Shanghai has multiple airports and that these results are for all airports serving the city.
The best day to arrive at Kuala Lumpur is Thursday and it would be best to avoid Sunday, as prices are on average 119.68% higher than on Thursday. (Average prices, based on 562 datapoints.)
The best time to fly is at around 18. (Average prices, based on 228 datapoints.)