Lung Lung Thun’s collection has been a long time in the making—though the relationship between luxury replica watches and owner has not always been easy. Lung Lung Thun whizzes around Singapore in her cherry-red Ferrari, down Orchard Road and past the city’s upscale shopping malls and high-fashion houses. It’s 2012, and the 23-year-old is hot off yet another spending spree. In the boot of her car are several unopened shopping bags from similar splurges. She comes to a stop light and bursts into tears. “I was buying so much and just couldn’t understand why,” she tells me over gin and tonics at Hong Kong’s The Upper House hotel. “I felt…